777F - SERV1828_TXT[1]

SERV1828 January 2007

GLOBAL SERVICE LEARNING TECHNICAL PRESENTATION

777F (JRP) OFF-HIGHWAY TRUCK INTRODUCTION

Service Training Meeting Guide (STMG)

777F (JRP) OFF-HIGHWAY TRUCK INTRODUCTION MEETING GUIDE 828

VISUALS AND SCRIPT AUDIENCE

Level II - Service personnel who understand the principles of machine system operation, diagnostic equipment, and procedures for testing and adjusting.

CONTENT This presentation provides basic maintenance information and describes the systems operation of the monitoring system, engine, power train, steering, hoist and brakes for the 777F Offhighway Truck. The Automatic Retarder Control (ARC) and the Traction Control System (TCS) are also discussed. This presentation may also be used for self-paced and self-directed learning. OBJECTIVES After learning the information in this meeting guide, the serviceman will be able to: 1. locate and identify the major components in the engine, power train, steering, and brakes; 2. explain the operation of the major components in the systems; and 3. trace the flow of oil through the systems. REFERENCES 777F (JRP) Operation and Maintenance Manual 777F (JRP) Parts Manual

SEBU7790 SEBP4305

PREREQUISITES "Fundamentals of Engines Self Study Course" "Fundamentals of Mobile Hydraulics Self Study Course" "Fundamentals of Power Trains Self Study Course" "Fundamentals of Electrical Systems Self Study Course" Estimated Time: 24 Hours Visuals: 224 Handouts: 30 Form: SERV1828 Date: 01/07 © 2007 Caterpillar Inc.

TEMV3001 TEMV3002 TEMV3003 TEMV3004

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SUPPLEMENTAL MATERIAL Reference Manuals Fluid Power Graphic Symbols User's Guide Cold Weather Recommendations for Caterpillar Machines Caterpillar Machine Fluids Recommendations

SENR3981 SEBU5898 SEBU6250

Salesgrams and Product Bulletins Training Bulletin "Caterpillar Transmission/Drive Train Oil" Product Bulletin "Reporting Particle Count By ISO Code" Salesgram "Caterpillar Extended Life Coolant" Product Data Sheet "Caterpillar Extended Life Coolant"

TEJB1002 PEJT5025 TEKQ0072 PEHP4036

Technical Instruction Modules on Legacy DVDs SERV1000-01 (These materials can not be ordered separately.) Automatic Retarder Control System Automatic Electronic Traction Aid 769C - 793B Off-highway Trucks--Suspension System Truck Payload Measurement System

SEGV2593 SEGV2585 SEGV2599 SEGV2579

Service Training Meeting Guides STMG 721 "777D Update (AGC) Off-highway Truck" (CD ROM)

SERV1721

Video Tapes Suspension Cylinder Charging TPMS Management/Technical Information TPMS Operating Tips Introduction to the Automatic Electronic Traction Aid Mining Trucks--Cleanliness and Component Life Oil Sampling--The Right Way

TEVN2155 AEVN2211 AEVN2212 SEVN9187 SEVN4142 PEVN4638

Booklets Know Your Cooling System Diesel Fuels and Your Engine Oil and Your Engine Understanding The S•O•S Report

SEBD0518 SEBD0717 SEBD0640 TEJB1015

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SUPPLEMENTAL MATERIAL (Continued) Special Instructions Accessing Flash Software for Machines Caterpillar Electronic Controls Service Code Information Description List Using the 7X1700 Communication Adapter Group Using the 261-3363 Wireless Communications Adapter Use of CE Connector Tools Servicing DT Connectors Parts Listing Of The Deutsch Connectors And Components Use of 6V3000 Sure-Seal Repair Kit Use of 8T5200 Signal Generator/Counter Group Suspension Cylinder Servicing 777F Assembly Procedure

REHS0494 REHS0126 SEHS9264 NEHS0926 SEHS9065 SEHS9615 REHS0148 SMHS7531 SEHS8579 SEHS9411 REHS2594

Brochures Caterpillar Electronic Technician Caterpillar DataView Diesel Engine Oil (CH4) Product Data Sheet How to Take a Good Oil Sample S•O•S Coolant Analysis Air Filter Service Indicator Cat Oil Cooled, Multiple Disc Brakes Caterpillar Automatic Retarder Control Caterpillar "D" Series Truck Cabs Caterpillar Truck Frames Mining Truck Bodies: Selecting The Right Body System For Your Job Caterpillar Truck Production Management System: Answering your questions about TPMS

NEHP5614 NEHP5622 PEHP8038 PEHP6001 PEHP5033 PEHP9013 AECQ5980 AEDK0075 AEDK0706 AEDK0707 AEDK0083 AEDK2953

Miscellaneous Pocket Card "Electronic Diagnostic Codes" Chart "Practical Pressure Conversions" "Cleaning Rear Axle Housing Assemblies (785/789)" Training CD-ROM "Caterpillar Electronic Technician (ET) for Off-highway Trucks" Training CD-ROM "Truck Production Management System (TPMS) for Off-highway Trucks"

NEEG2500 SEES5677 SEBF8366 SERV7003 SERV7004

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TABLE OF CONTENTS INTRODUCTION ........................................................................................................................7 MAINTENANCE .......................................................................................................................11 OPERATOR'S STATION............................................................................................................38 MONITORING SYSTEM ..........................................................................................................47 Messenger Display Module ..................................................................................................52 Advisor/VIMS Display .........................................................................................................63 ENGINE......................................................................................................................................83 Engine Electronic Control System .......................................................................................84 Engine Derates......................................................................................................................94 Engine Compression Brake ................................................................................................101 Cooling System...................................................................................................................106 Lubrication System .............................................................................................................108 Fuel System.........................................................................................................................109 Air Intake and Exhaust System ..........................................................................................116 POWER TRAIN .......................................................................................................................124 Torque Converter Hydraulic System ..................................................................................127 Transmission Hydraulic System .........................................................................................138 Rear Axle ............................................................................................................................150 Transmission/Chassis Electronic Control System ..............................................................152 STEERING SYSTEM ..............................................................................................................163 HOIST SYSTEM ......................................................................................................................177 BRAKE SYSTEM ....................................................................................................................197 Brake Electronic Control System .......................................................................................224 Automatic Retarder Control System...................................................................................229 Traction Control System.....................................................................................................231 CONCLUSION.........................................................................................................................238 VISUAL LIST ..........................................................................................................................239 HYDRAULIC SCHEMATIC COLOR CODE.........................................................................242 HANDOUTS.............................................................................................................................243 POSTTEST ...............................................................................................................................268 POSTTEST ANSWERS ...........................................................................................................272

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777F (JRP) OFF-HIGHWAY TRUCK INTRODUCTION

© 2006 Caterpillar Inc.

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INTRODUCTION Shown is the right side of a 777F Truck. The fuel tank is located on the right side of the truck. The 777F Truck comes standard with oil-cooled multiple disc brakes, front and rear. Front caliper type disc brakes are available as an option. The major features added to the 777F Truck are: the new cab, the Messenger or VIMS Advisor monitoring system, the Tier 2 compliant C32 ACERT™ engine and cooling system, the ECPC transmission, and the hydraulic brakes. Some of the specifications of the 777F Truck are: - Serial No. Prefix: JRP - Empty weight: 73976 kg (163090 lb) - Load carrying capacity: 90.9 tonnes (100 tons) - Gross Machine Weight (GMW): 163293 kg (360000 lb) - Length: 10.5 m (34.5 ft) - Operating Width: 6.5 m (21.3 ft) - Height: 5.2 m (17.0 ft) - Body Up Height: 10.4 m (34.0 ft) - Top speed, loaded: 64.5 km/h (40.1 mph)

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Shown is the left side of a 777F Truck. The hydraulic tank group is visible. The hydraulic tank group consists of two separate tanks: the hoist, brake, and torque converter hydraulic tank (front) and the transmission hydraulic tank (rear). The transmission hydraulic system is separated from all of the other hydraulic systems. The Individual Clutch Modulation (ICM) transmission has been replaced with Electronic Clutch Pressure Control (ECPC) transmission. The Chassis/Transmission Electronic Control System controls most of the same functions as on the 777D truck. The air system has been eliminated on the 777F Truck. The brakes are completely hydraulic.

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Shown is the front of a 777F Truck. The 777F Truck uses a Next Generation Modular Radiator (NGMR). Its modular design, similar to the previous folded core radiator, permits easy removal of a single core without having to remove the entire radiator.

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Shown is the rear of a 777F Truck. Two body options are available for the 777F Truck: - A dual-slope steel design with a "V" bottom main floor to reduce shock loading, center the load, and reduce spills. - The dual-slope steel body above, with the addition of a rubber liner for increased resistance to impact and wear. All internal wear surfaces of the truck body are made with 400 Brinell hardness steel. The steel attachment body liner is also made with 400 Brinell hardness steel. The external components of the body are made of steel with a yield strength of 6205 bar (90000 psi). The rubber liner is one-fifth the density of steel, but absorbs impact four times better. The rear suspension cylinders absorb bending and twisting stresses rather than transmitting them to the main frame.

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777F MAINTENANCE e 777F Servic Procedure

WALK AROUND INSPECTION 5

MAINTENANCE Before working on or operating the truck, read the Operation and Maintenance Manual thoroughly for information on safety, maintenance, and operating techniques. Safety precautions and Warnings are provided in the manual and on the truck. Be sure to identify and understand all symbols before starting the truck. The first step to perform when approaching the truck is to make a thorough walk around inspection. Look around and under the truck for loose or missing bolts, trash build-up and for coolant, fuel or oil leaks. Look for indications of cracks. Pay close attention to high stress areas as shown in the Operation and Maintenance Manual.

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10 HOURS DAILY MAINTENANCE CHECKS Steering Oil Level

Fuel Level and Drain Moisture

Primary Fuel Filter Disconnect Switch Suspension Cylinder Height

Engine Oil Level Batteries Air Filters and Precleaners

Rear Axle Breather

Radiator Debris Fan Belts and Ether Cylinder Coolant Level

Inspect Frame for Cracks and Body Support Pads Check For Leaks and Trash Build-up

Wash Windows, Cab Fresh Air Filters, Seat Belt, Indicators, Gauges, Brake Tests, Secondary Steering and Back-up Alarm Windshield Washer Level

Tire Inflation Pressure

Suspension Cylinder Height and Grease Breathers Wheel Nuts Hoist, Converter And Brake Oil Level

Transmission Oil Level

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The following list identifies the items that must be serviced every 10 Hours or Daily. - Walk-Around Inspection: Check for loose or missing bolts, leaks, trash build-up, and cracks in frame structures and body support pads. - Back-up alarm: test - Brakes, indicators, gauges: test - Braking system: test - Coolant level - Differential / final drive oil level - Engine air filter service indicator - Engine oil level - Engine oil level (ORS)

- Engine oil level: log additions - Fuel filter: drain water separator - Fuel tank: drain water / sediment - Hoist, converter, brake oil level - Seat belt: inspect - Secondary steering: test - Steering system oil level - Transmission oil level

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The front wheel bearing oil level is checked and filled by removing the plug (1) in the center of the wheel bearing cover. The oil should be level with the bottom of the plug hole. The fill plug is a magnetic plug. Inspect the fill plug weekly for metal particles. If any metal particles are found, remove the wheel cover and inspect the bearings for wear. When draining the oil, rotate the wheel so the drain plug (2) is at its lowest position. The service interval for changing the front wheel bearing oil is 500 hours. Use Final Drive and Axle Oil (FDAO) or commercial FD-1. As a substitute, Transmission Drive Train Oil (TDTO) with a commercial TO-4 may be used. Check the tire inflation pressure. Operating the truck with the wrong tire inflation pressure can cause heat build-up in the tire and accelerate tire wear. Caterpillar recommends inflating tires with dry nitrogen instead of air to reduce heat build-up and potential combustion. Nitrogen also slows rubber deterioration and rim corrosion. NOTE: Care must be taken to ensure that fluids are contained while performing any inspection, maintenance, testing, adjusting, and repair of the machine. Be prepared to collect the fluid in suitable containers before opening any compartment or disassembling any component containing fluids. Refer to the "Tools and Shop Products Guide" (Form NENG2500) for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose of fluids according to local regulations and mandates.

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Check the front suspension cylinders for leaks or structural damage. Check the charge condition of the front suspension cylinders when the truck is empty and on level ground. Measure the charge height of the suspension cylinders and compare the dimension with the dimension that was recorded the last time the cylinders were charged. Recharge the cylinders with oil and nitrogen if necessary. A grease outlet fitting (arrow) is located on one side of each front suspension cylinder. The grease supply fitting is located on the opposite side of the suspension cylinder. No grease outlet fittings should be located on the same side of the suspension cylinder as the grease fill location. Having an outlet fitting on the same side of the suspension cylinder as the grease fill location will prevent proper lubrication of the cylinder. Make sure that grease is flowing from the outlet fittings to verify that the suspension cylinders are being lubricated and that the pressure in the cylinders is not excessive. NOTE: For more detailed information on servicing the suspension system, refer to the Special Instruction "Suspension Cylinder Servicing" (Form SEHS9411).

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If the machine is equipped with the optional caliper type front brakes, inspect the brake linings (1) for wear. The thickness of the brake linings (not including carrier) must not be less than 3.15 mm (.125 in). Measure the lining at both ends because one end can wear more than the other. The clearance between the brake carrier guide pins (2) and the brake disc (3) must not be less than 1.5 ± 0.5 mm (.06 ± .02 in.).

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The primary fuel filter (1) is mounted between the right front wheel and the engine cooling fan. A reusable fuel/water separator mounts directly to the filter element. Periodically open the valve (2) under the separator bowl and drain any water into an approved container. After changing fuel filters, hold the switch (3) upward to activate the electric fuel priming pump to refill the fuel lines and filters with fuel.

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The dual engine oil filters (1) are located on the right front of the engine. Engine oil samples can be taken at the S•O•S tap (2) located on the front of the oil filter base. The secondary fuel filter (3) is located at the right front of the engine, in front of the engine oil filters. A fuel filter bypass switch (4) is located on the filter base. The bypass switch provides an input signal to the Engine ECM indicating if the filters are restricted. Jacket water coolant samples can be taken at the Scheduled Oil Sampling (S•O•S) coolant analysis tap (5). The coolant tap is located behind the engine oil filters. The bottom illustration shows the coolant tap with the filter removed.

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The transmission filters (1) are located behind the fuel tank and under the center tube. Transmission oil samples can be taken at the S•O•S tap (2). The oil filter bypass switch (3) provides input signals to the Transmission/Chassis ECM. The ECM sends a signal to the monitoring system in the cab to warn the operator when the filter is restricted. A pressure test port (4) is available for monitoring charge pressure for the transmission control valves.

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Located in front of the fuel tank on the right side of the truck is the torque converter charging filter (1). Hoist, converter, and brake oil samples can be taken at the S•O•S tap (2) at the base of the filter.

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The fuel tank is located on the right side of the truck. The fuel level sight gauge (1) is used to check the fuel level during the walk around inspection. A fuel level sender is located on the fuel level sight gauge. The fuel level sender provides input signals to the monitoring system, which informs the operator of the fuel level. Open the drain valve below the tank to remove condensation and sediment from the fuel tank. Inspect the condition of the fuel tank breather (above tank) and the fuel fill cap (2) at regular intervals. Fuel can be added at the attachment quick service fuel fill connector (3).

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The rear axles are equipped with planetary-type final drives. Rotate the final drive until the drain plug (1) is at the lowest position, as shown. The final drive oil level is checked and filled by removing the magnetic plug (2). The oil should be level with the bottom of the plug hole. Fill the rear axle housing with oil before filling the final drives with oil. Allow enough time for the oil to settle in all of the compartments. This time allowance can be as much as 20 minutes during cold temperatures. The oil is drained by removing the drain plug. The magnetic inspection plugs should be removed weekly from the final drives and checked for metal particles. For some conditions, checking the magnetic plugs is the only way to identify a problem which may exist. Use FDAO (Final Drive and Axle Oil) or Transmission Drive Train Oil (TDTO) with a specification of TO-4 or newer. These oils provide: - Maximum frictional capability required for gears - Increased lubrication capability for bearings NOTE: The rear axle is a common sump for the differential and both final drives. If a final drive or the differential fails, the other final drive components must also be checked for contamination and then flushed. Failure to completely flush the rear axle after a failure can cause a repeat failure within a short time.

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Check the differential oil level by removing the magnetic inspection plug (1). The oil should be level with the bottom of the fill plug opening. Inspect the rear suspension cylinders for leaks or structural damage. Check the charge condition of the rear suspension cylinders when the truck is empty and on level ground. Measure the charge height of the suspension cylinders, and compare the dimension with the dimension that was recorded the last time the cylinders were charged. Recharge the cylinders if necessary. Inspect the condition of the rear axle breather (2) at regular intervals. The breather prevents pressure from building up in the axle housing. Excessive pressure in the axle housing can cause brake cooling oil to leak through the Duo-Cone seals in the wheel brake assemblies. NOTE: For more detailed information on servicing the suspension system, refer to the Special Instruction "Suspension Cylinder Servicing" (Form SEHS9411).

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The body up retaining pins are stored inside a cross-tube (1) in a body support beam directly above the retaining bracket (2). When work is to be performed while the body is raised, the body up retaining pins must be installed through the holes in the body retaining bracket and the rear frame support (3) to hold the body in the raised position. The body is shown in the lowered position.

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Shown are the transmission hydraulic tank (1) and the hoist, converter, and brake hydraulic tank (2). Both tanks are equipped with oil level sight gauges. The oil level of both hydraulic tanks should first be checked with cold oil and the engine stopped. The level should again be checked with warm oil and the engine running. The lower sight gauge (3) on the hoist, converter, and brake hydraulic tank can be used to check the tank level when the hoist cylinders are in the RAISED position. When the hoist cylinders are lowered, the hydraulic oil level will increase. After the hoist cylinders are lowered, check the hydraulic tank oil level with the upper sight gauge (4). Check lower transmission oil sight gauge (5) with the engine off and oil cold. Use the upper gauge (6) with engine at idle and oil warm. Inspect the hoist, converter, and brake hydraulic tank breather for plugging. The breather is located on the frame rail above the hydraulic tank. Inspect the condition of both hydraulic tank fill cap vents (located on top of the tank) at regular intervals. When filling the hydraulic tanks after an oil change, fill the tanks with oil to the FULL COLD mark on the sight gauge. Turn on the engine manual shutdown switch so the engine will not start. Crank the engine for approximately 15 seconds. The oil level will decrease as oil fills the hydraulic systems. Add more oil to the tanks to raise the oil level to the FULL COLD mark. Crank the engine for an additional 15 seconds. Repeat this step as required until the oil level stabilizes at the FULL COLD mark.

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Turn off the engine manual shutdown switch and start the engine. Warm the hydraulic oil. Add more oil to the tank as required to raise the oil level to the FULL WARM mark. In both tanks, use only Transmission Drive Train Oil (TDTO) with a specification of TO-4 or newer. TDTO TO-4 oil has the following features: - Provides maximum frictional capability required for clutch discs used in the transmission, torque converter and brakes. - Increases rimpull because of reduced slippage. - Increases brake holding capability by reducing brake slippage. - Controls brake chatter. - Provides maximum frictional capability required for gears.

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Before climbing the truck ladder, make sure that the manual engine shutdown switch (1) is OFF. The switch is located below the cab at the base of the left stairway. The engine will not start if the manual shutdown switch is ON. If necessary, the switch can be used to stop the engine from the ground level. The access light switch (2) is used to turn on or turn off the lighting in the area around the stairs. There is a second access light switch on the left side of the dash in the cab.

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While climbing the ladder, make a thorough inspection of the radiator. Be sure that no debris or dirt is trapped in the radiator cores. The battery disconnect switch is located under a cover (1) on the front bumper near the right access ladder. If the machine is being parked for an extended period (overnight, etc.) turn off the disconnect switch and remove the key. The machine lockout and engine lockout switches are located behind an access cover (2) between the radiator cowling and the right stairway.

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This illustration shows the engine disconnect switch (1) and the auxiliary start receptacle (2).

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The engine lockout control switch (1) allows the engine to be safely locked out while service is performed. The engine must be stopped to activate the engine lockout mode. When the engine lockout mode is activated, the following conditions exist: - The engine starter is disabled. - The secondary steering is disabled. - The prelube function is disabled. The following conditions must be met before the engine lockout mode will activate: - The transmission control must be in the PARK position. - The engine must be OFF. When the switch is activated, one of the following results will occur: - The indicator lamp (2) will illuminate continuously to indicate that the machine is in the engine lockout mode. - The indicator lamp will flash to indicate that the engine lockout mode will not activate until the transmission control is in the PARK position and the engine is OFF.

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The machine lockout control switch (3) allows the machine to be safely locked out while service is performed. When the machine lockout mode is activated, the following conditions exist: - The engine will start. - The transmission is disabled. - The hoist is disabled. - The steering is disabled. - The machine lockout mode indicator (4) will illuminate after the key start switch is turned on. NOTE: The lockout mode indicator on the dash panel will illuminate when the engine lockout control or the machine lockout control is activated. Also located near the lockout switches are the following circuit breakers: - 90 Amp Alternator (5) - 15 Amp Engine (6) - 80 Amp Starter Solenoid (7)

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24 The batteries are located inside the front bumper, at the base of the radiator cowling (1). Inspect the battery connections for corrosion or damage. Keep the battery terminals clean and coated with petroleum jelly. Inspect the electrolyte level in each battery cell, except maintenance free batteries. Maintain the level to the bottom of the fill openings with distilled water. The coolant level on the 777F is checked with the jacket water coolant sight gauge (2) located below the cab on the side of the front cowling. Coolant is added by removing the radiator cap (3) located inside an access door on the upper deck. The water used in the cooling system is critical for good cooling system performance. Use distilled or deionized water whenever possible to prevent acids or scale deposits in the cooling system. Acids and scale deposits result from contaminants that are found in most common water sources. Never use water alone. All water is corrosive at engine operating temperatures without coolant additives. Also, water alone has none of the lubrication properties that are required for water pump seals. Cat trucks are filled at the factory with Extended Life Coolant (ELC). If ELC is maintained in the radiator, it is not necessary to use a supplemental coolant additive. Do not use a conventional coolant to top-off a system filled with Cat ELC. An acceptable substitute for ELC is a Cat DEAC (Diesel Engine AntiFreeze/Coolant) or a commercial heavy-duty coolant/antifreeze that meets ASTM D4985 or ASTM D6210 specifications.

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The steering system hydraulic tank is located on the right platform. Check the steering system oil level at the sight gauge (1), on the side of the tank. The steering system oil filter (2) cleans the oil before it enters the hydraulic tank. The steering system uses a pressure compensated piston-type pump mounted to the rear of the engine. Case drain oil from the steering pump returns to the steering tank through a case drain filter (3). Before removing the fill cap (4) to add oil to the steering system, depress the pressure release button (5) on top of the breather to release any pressure from the tank. The steering system filter base and the case drain filter base have bypass valves that allow the steering oil to bypass the filters if they are plugged.

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Shown are the air intake system components. Check the air filter restriction indicator (1). If the yellow piston is in the red zone, the air filters are restricted and must be serviced. The air filter housing covers serve as the precleaner assemblies. When servicing the filter elements, clean the precleaners (2) and dust valves (3) using air or water pressure, or detergent wash. The dust valve is OPEN when the engine is OFF and closes when the engine is running. The dust valve must be flexible and closed when the engine is running or the precleaner will not function properly and the air filters will have a shortened life. Two filter elements are installed in the filter housings. The large element is the primary element and the small element is the secondary element. Air intake system tips: - The primary element can be cleaned a maximum of six times. - Never clean the secondary element for reuse. Always replace the secondary element. - Air filter restriction causes black exhaust smoke and low power.

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The engine oil level dipstick (1) and the engine oil fill tube (2) are located inside the access cover for the air filters. Check the engine oil level with the dipstick and add engine oil at the fill tube. Caterpillar recommends multigrade Diesel Engine Oil (DEO) with a specification of ECF-1. API CH-4, CI-4, and CI-4 Plus oils are only acceptable if they meet ECF-1 specifications. DEO oils with a CG-4 specification are acceptable, but should be limited to 250-hour oil change intervals. CF and older oils should not be used in Caterpillar diesel engines. Cat ECF-1 Specification was established by Caterpillar in 2003 and requires excellent soot dispersion, wear control, and piston deposit control.

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To check the fluid level of the windshield washer reservoir, open the access door located at the left rear of the cab, behind the cab door. Open the filler cap (1) to check the fluid level and fill as necessary. To the left of the filler spout is the air conditioner filter (2). Clean or replace the filter element when a reduction of circulation in the cab is noticed.

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The remaining 10 Hours or Daily checks are performed in the operator's compartment: - Brakes: Check operation - Indicators and gauges: Test operation - Seat belt: Inspect - Back-up alarm: Test operation - Secondary steering: Test operation The service brakes are checked by depressing the pedal (1) and placing the shift lever in FIRST FORWARD. Accelerate the engine until the truck moves. The truck must not move below 1200 rpm. This procedure should be repeated to test the secondary brakes by depressing the secondary brake pedal (2). The cab air filter (3) is located inside the cab door, in the left-rear corner behind the trainer seat. Clean or replace the cab fresh air filter when necessary. NOTE: Refer to the Operation and Maintenance Manual for information on the remaining tests performed in the cab.

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This illustration shows the cab air filter (1) located behind the trainer seat (2).

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OPERATOR'S STATION Shown is a view of the 777F operator compartment. The operator's station for the 777F has been changed to improve operator comfort and ergonomics. The operator seat (1) is centered in the cab with the trainer's seat (2) positioned to the left. The hoist control lever (3) is now on the right console next to the transmission control lever (4). The 777F is equipped with a standard Messenger Monitoring System or optional VIMS/Advisor Monitoring System (shown). The optional Caterpillar Work Area Vision System (WAVS) is a closed circuit video monitoring system. WAVS consists of a 178mm (7 inch) LCD color display (5) and may include one, two, or three cameras. The display is mounted in the machine cab. The cameras are mounted on the frame of the machine. The location of the camera(s) is dependent on the machine type.

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The Truck Production Management System (TPMS) on the 777F is controlled by a TPMS ECM if the machine is equipped with Messenger or a VIMS ECM if the machine is equipped with VIMS/Advisor. There are two sets of TPMS external loading lamps on the truck. One set of lamps is on the left side of the cab (arrow) and the other set is on the right platform. The lamps are green and red. The lamps inform the loader operator of the loading progress toward a target payload weight. The lamps are active only during the loading cycle and are off at all other times. During loading, the green (continue loading) lamps will be ON until the payload is 95% of the target weight setting. Then, the red (stop loading) lamp will light. A "last pass" indication can be programmed into the system. With last pass indication, the TPMS calculates an average loader pass size and predicts payload weight. If the predicted weight after the NEXT loader pass will be above 95% of the target weight setting, the red lamps FLASH. The red lamps will be ON continuously after the last pass (when fully loaded). A minimum of three loader passes are required for the "last pass" indication option to function correctly. The actual measured weight of the material in the truck body is displayed on the Messenger display or the VIMS/Advisor display.

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Located on the left side of the front panel are: - Telescopic/tilt steering column adjustment lever (1): Push for telescoping and pull for tilt. - Intermittent wiper/washer, turn signal control, and dimmer switch (2). - Steering wheel mounted electric horn control (3). - Light switches and hazard warning switch (4). The instrument panel (5) includes a tachometer, four gauges, and several indicators that display the machine systems status. An LCD screen displays the service hour meter, machine ground speed, actual gear, and direction.

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9 10

1 2

3

4

5

6

34

Located on the right side of the steering column is the retarder lever (1). The retarder lever is used to modulate engagement of the service brakes. The retarder lever engages the front and rear brakes on trucks with the standard oil-cooled front brakes but engages but only the rear brakes on trucks with the optional caliper disc front brakes. The retarder lever can control the modulation of the service brakes more precisely than the service brake pedal located on the cab floor. Located on the dash to the right of the retarder lever are the key start switch (2), fan speed switch (3), temperature variable knob (4), air conditioner switch (5), and cigarette lighter (6). Above the HVAC controls is the optional VIMS/Advisor display (7). Switches to the left of the VIMS/Advisor display are the ARC ON/OFF switch (8), compression brake switch (9), and front brake switch (10) (if equipped).

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Text Reference

2 4

3 1 5

35

To the right of the operator's seat is the shift console which contains the transmission shift lever (1) and the hoist control lever (2). The 777F truck has SEVEN speeds FORWARD and ONE REVERSE. The top gear limit and body up gear limit are programmable through the Transmission/Chassis ECM. The top gear limit can be changed from THIRD to SEVENTH. The body up gear limit can be changed from FIRST to THIRD. The 777F truck hoist system is electronically controlled. The hoist control lever activates the four positions of the hoist control valve. The four positions are: RAISE, HOLD, FLOAT, and LOWER. A fifth position of the hoist valve is called the SNUB position. The operator does not have control over the SNUB position. The body up switch controls the SNUB position of the hoist valve. When the body is lowered, just before the body contacts the frame, the Transmission/Chassis ECM signals the hoist solenoids to move the hoist valve spool to the SNUB position. In the SNUB position, the body float speed is reduced to prevent hard contact of the body with the frame. The truck should normally be operated with the hoist lever in the FLOAT position. Traveling with the hoist in the FLOAT position will make sure the weight of the body is on the frame and body pads and not on the hoist cylinders. The hoist valve will actually be in the SNUB position.

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Text Reference

If the transmission is in REVERSE when the body is being raised, the hoist lever sensor is used to shift the transmission to NEUTRAL. The transmission will remain in NEUTRAL until: 1. the hoist lever is moved into the HOLD or FLOAT position; and 2. the shift lever has been cycled into and out of NEUTRAL. The hoist lever is also used to start a new TPMS cycle. NOTE: If the truck is started with the body raised and the hoist lever in FLOAT, the lever must be moved into HOLD and then FLOAT before the body will lower. The throttle backup and throttle lock switch (3), the WAVS alternate camera system switch (4) (if equipped), and a 12V power port (5) are also located on the shift console.

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1

2

Text Reference

3

36

The overhead console can be equipped with three switches. The optional heated mirrors switch (1) controls the heated mirrors. The TCS test switch (2) is used to perform the TCS test when the switch is held. The brake release/secondary steering switch (3) manually activates the brake release and secondary steering pump when the switch is held.

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Text Reference

3 1

2

37

Located on the floor of the cab are: - Secondary brake pedal (1): Used to modulate application of the parking brakes on the rear wheels. A position sensor is attached to the secondary brake pedal that provides input signals to the Brake ECM. - Service brake pedal (2): The service brake pedal is used to modulate engagement of the service brakes on all four wheels if the front brake ON/OFF switch is in the ON position. A position sensor is attached to the service brake pedal that provides input signals to the Brake ECM. - Throttle pedal (3): A throttle position sensor is attached to the throttle pedal. The throttle position sensor provides the throttle position input signals to the Engine ECM.

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Text Reference

1

2 3

6

4

5

38

Located behind the trainer's seat are the fuse panels (1), the Cat ET service port (2), the TPMS or VIMS service port (3), the Product Link service port (4), a 12V power receptacle (5), and the 20 amp heater/air conditioner fan circuit breaker (6).

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Text Reference

777F ELECTRONIC SYSTEM BLOCK DIAGRAM

Telemetry Antenna (Attachment)

VIMS-PC

GPS Antenna (Attachment)

Inclinometer (Attachment)

Instrument Cluster

10

15

20

25

5

30

OK

35

0

X100

Messenger Module ( St andard)

TCS

VIMS / Advisor ( Opt ional)

Engine ECM (A4:E4)

Minestar Display

CAT Datalink CAN SAE J1939 Datalink RS232 19200 Baud Serial Link

Minestar Control (Attachment)

VIMS ECM (Advisor) (ABL2M) (Attachment) Road Analysis ECM (RAC) (ABL2M) (Attachment) Brake ECM (TCS) (A4:M1) (Standard) Trans / Chassis ECM (A4:M1) (Standard)

Product Link ECM (Attachment) ET Service Tool

TPMS ECM ( ABL2 M) ( At t achment )

39

MONITORING SYSTEM The monitoring system on the 777F Off-highway Trucks monitors various machine systems and then conveys the machine status to the operator. The 777F can be equipped with the standard monitoring system which includes a Messenger display module, or the optional monitoring system which includes a VIMS/Advisor display module. Both monitoring systems include an instrument cluster. The instrument cluster is a cab display that shows the operator the status of various machine parameters and alerts the operator of specific machine conditions. The ECMs and monitor display modules communicate over the Cat Data Link. The display modules communicate with the instrument cluster over the Can Data Link. The monitoring system receives information from machine switches and sensors via the ECMs shown in this illustration of the Machine Electronic Control System. The 777F can also have the following attachments: Minestar, RAC, Product Link, Inclinometer, Telemetry antenna, and GPS antenna.

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Text Reference

1

2

40

The instrument cluster (1) and optional VIMS/Advisor display panel (2) are shown is this illustration. The standard Messenger module (not shown) is installed in the same location as the VIMS/Advisor display panel. Problems from the machine systems are classified into four warning categories (1, 2, 2S, and 3) similar to other Caterpillar monitoring systems. During the normal operation mode and the menu mode, the Messenger or VIMS/Advisor display may be interrupted by a warning message. Warning messages are displayed when important instructions or information need to be displayed. The Messenger or VIMS/Advisor provides three Warning Categories. The first category requires only operator awareness. The second category states that the operation of the machine and the maintenance procedure of the machine must be changed. The third Warning Category states that the machine must be safely shut down immediately. Warning Category 1 For a Category 1 Warning, an indicator light will illuminate or a gauge will be in the red zone. The indicator that illuminates or the gauge that is in the red zone identifies the machine system that needs attention. The "OK" key on the Messenger or VIMS/Advisor panel can be used to acknowledge the warning. Some warnings will be silenced for a predetermined period. After this time period, if the abnormal condition is still present, the warning will reappear.

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Text Reference

Warning Category 2 For a Category 2 Warning, an indicator will illuminate or a gauge will indicate in the red zone, the action light will flash, and a popup screen appears on the Messenger or VIMS/Advisor display screen. A Category 2 warning alerts the operator that a change in machine operation is required to avoid possible damage to the indicated system. The "OK" key on the Messenger or VIMS/Advisor panel can be used to acknowledge the warning. Some warnings will be silenced for a predetermined period. After this time period, if the abnormal condition is still present, the warning will reappear. Warning Category 2-S For a Category 2-S Warning, an indicator will illuminate or a gauge will indicate in the red zone, the action light will flash, a popup screen appears on the Messenger or VIMS/Advisor display screen, and an action alarm will sound continuously. The 2-S Warning indicates a SEVERE Category 2 Warning. A Category 2-S Warning alerts the operator to immediately change the operation of the machine to avoid possible damage to the indicated system. When the change in operation is made to an acceptable condition, the action alarm will turn off. Warning Category 3 For a Category 3 Warning, an indicator will illuminate or a gauge will indicate in the red zone, the action light will flash, a popup screen appears on the Messenger or VIMS/Advisor display screen, and an action alarm will sound intermittently. A Category 3 Warning alerts the operator that the machine must be safely shut down immediately to avoid damage to the machine or prevent personal injury. Some Category 3 Warnings cannot be stopped by pressing the "OK" key.

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4

Text Reference

1 5

3

6 2

41

Shown is the Instrument Cluster located in the center of the front dash panel. The Instrument Cluster includes 18 dash indicators, five analog gauges, and an LCD digital display (1). The LCD display window in the lower center of the dash includes the truck speed, gear, and direction on the top of the display and the service hour meter on the bottom of the display. The five parameters monitored by the analog gauges are: - Brake oil temperature (2) - Engine coolant temperature (3) - Engine speed (4) - Torque Converter oil temperature (5) - Fuel Level (6)

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Text Reference

INSTRUMENT CLUSTER Park Brake Engaged Brake System Check

Power Train System Check

Action Lamp

Engine RPM

Electrical System Body Up Transmission in Reverse Machine Lockout Active

Check Engine

High Beam Secondary Steering Engaged

Retarder Engaged

Engine Coolant Temperature Gauge

Traction Control System Engaged

15

Primary Steering Loss

10 5

20 X100 n/min

25

R

Throttle Lock

Left Turn Signal Truck Speed

0

n/min

30 mph km/h

Machine Immobilizer Right Turn Signal Active Gear and Direction

kPa psi

Brake Oil Temperature Gauge

Torq Converter Oil Temperature Gauge

LCD Display Window

Fuel Level Gauge

Service Hour Meter

42 The indicator lamps and gauges are shown in this illustration.

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Text Reference

MESSENGER DISPLAY MODULE DEFAULT SCREEN

Message Bar P R N 1 2 3 4 5 6 7 OK

43

Messenger Display Module Shown is the standard Messenger display module, which is located in the right side of the front dash. The purpose of the Messenger is to display relevant machine information to the operator or service personnel. The Messenger display is used in conjunction with the instrument cluster to act as the monitoring system for the machine. The Messenger has a menu structure that allows the user to access the desired machine information. The default screen will display under normal machine operating conditions without any intervention from the operator or service personnel. This illustration shows the default screen of the Messenger module that shows the shift lever and the gear position. The default screen is displayed at machine start up and until the operator or the technician navigates to another screen. The Messenger consists of the display and four navigation buttons that are used to navigate through the menu structure. The button functions from left to right are as follows: Back: Used to navigate to the previous screen that was accessed in the Messenger. Left/Up: Allows the user to scroll left or up. Scroll direction is dependent on the specific data that is being displayed on the screen. Right/Down: Allows the user to scroll right or down. Scroll direction is dependent on the specific data that is being displayed on the screen. OK: Acts as a confirmation function for the Messenger.

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Text Reference

MAIN MENU SELECTION

Performance

Main Menu

Totals

Performance Default

Settings

OK Service

Service Mode

44

The Messenger Menu Screen is divided into three sections. The top section identifies the name of the current menu. If the current name is split by a colon ":" then this indicates that the name after the colon ":" is the current menu and the name before the colon ":" is the parent menu of the current menu. The center section displays the current menu option that can be selected by pressing the OK button. The arrows at the left of the screen indicate whether you can scroll to the next screen to see further menu options. There are a total of five main menus that are available for navigation. Only one menu can be displayed at a time. The menus are accessed from the default menu by pressing the back arrow button. The five menus are: - Performance - Totals - Settings - Service - Service mode

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Text Reference

PERFORMANCE SCREEN SUBMENU

Eng Coolant Temp

Shift Lever

85° C

N

OK

45

This illustration of a performance screen submenu shows the engine coolant temperature and shift lever position. A typical Messenger information screen normally displays the information in pairs. The headers at the top of the screen identify the information. The current values are displayed below the headers. The arrows at the left of the screen indicate whether you can scroll to the next screen to see additional information.

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Text Reference

PERFORMANCE MENU SELECTION

Engine Coolant Temperature

Engine Oil Pressure

Engine Speed

Inlet Air Temperature

Hydraulic Oil Temperature

Fuel Level

Torque Converter Temperature

Battery Voltage

Main Menu Performance Performance

OK

46

The Performance menu allows the operator or technician to view two pages of information. These pages of information monitor vital machine system data during machine operation. This information can only be viewed. The Performance menu uses two screens to show the real time status of the information listed above on the right side of the illustration.

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Text Reference

TOTALS MENU SELECTIONS

Total Load Count

Load Count

Reset Load Count Yes

Main Menu

Payload

Totals

Accum Wt

Loaded Time

OK Loaded Dist

Reset Load Count No

Totals

Distance Traveled

Machine Hrs Machine Total Fuel

Blank

47

The Totals main menu allows the operator or the technician to access information about the machine systems. The totals data can be used to determine when scheduled maintenance is required. The Totals menu shows accumulated values and includes two submenus. The two submenus are Payload and Machine. The Payload and Machine submenus display the information listed on the right side of the above illustration.

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Text Reference

SETTINGS MENU SELECTION Main Menu Settings OK

48

Parameters are normally adjusted for specific operating conditions, operator preferences, and machine operating efficiency. The machine setup affects the parameters that are displayed. The attachments that are on the machine determine the software that is contained in the ECMs. Messenger looks at the software versions to determine the parameters that will be displayed and the parameters that will be variable. NOTE: Cat ET can also be used to access the parameters. The Settings menu allows the user to adjust the parameters for the following: - Messenger Display - Machine Identification - Transmission Operation - Brake Operation - Payload Operation - Engine Operation

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Text Reference

The Messenger Display parameters relate to the operator’s preferences for the Messenger display. The following parameters may be adjusted: - Language: Six standard languages (other languages available). - Units: Metric or English. - Contrast: Screen contrast. - Headlights On: Screen brightness with headlights ON. - Headlights Off: Screen brightness with headlights OFF. The Machine settings allow the user to set the machine serial number. The following parameters may be adjusted: - Product ID: Allows the user to set the machine serial number (password protected). - Equipment ID: Allows the name of the truck to be changed (password protected). The Transmission setting allows the following parameters to be adjusted: - Top Gear Limit: Allows the user to set the highest gear performance level. - Body Up Gear Limit: Adjusts the gear limit during truck operation when the body is raised. - Machine Speed Limit: Sets the highest truck speed. - Fuel Economy Mode: Allows the fuel usage to be changed. - Machine Overload Speed Limit: Limits transmission gear and engine speed when excessive payloads are detected (if machine is equipped with TPMS). The Brake setting allows the user to set the desired ARC speed and is password protected. The Payload menu allows the configuration of the Payload settings and is password protected. The Payload settings include the following: - Target Payload: Read and program the truck target payload. - Overload Limit: Read and program the percent overload. - Green TPMS Lamp: Read and program the installation of the green TPMS lamp. - Red TPMS Lamp: Read and program the installation of the red TPMS lamp. - Last Pass Enabled: Read and program the installation of the Last Pass indicator. The Last Pass indicator informs the shovel operator of the last load before the payload is over the rated load. The Engine setting allows the user to change the ether solenoid configuration to "No Ether Solenoid Installed" or "Continuous Flow" and is password protected.

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Text Reference

SERVICE MENU SELECTION Service Diagnostic Events OK

49

The Service menu allows the technician to access the machine parameters. The technician may also make selections for viewing or clearing logged events or codes. The Service menu will allow the technician to view data for the following systems: the brake, the steering, the implement, and the power train. The status of electronic components in the machine’s major systems can also be viewed. The Service menu option is displayed by selecting Service from the Main Menu. Press the Left/Up arrow button or the Right/Down arrow button until Service is displayed. Then press the OK button. The Service menu contains the following six submenus: - Diagnostic Events: Displays a complete list of all active and inactive event codes and diagnostic codes. - System Parameters: Allows the technician to view the status of system components. - Calibrations: Allows the technician to perform a payload calibration. The payload system must be calibrated if new TPMS software is installed or the suspension is charged. - System Tests: Allows the user to perform a transmission stall test or a system self test on the machine. - Systems Information: Allows the user to display information on all of the ECMs installed on the machine, such as ECM Part Number, etc. - Tattletale: The Messenger display module records the extreme value for each condition of the machine that is monitored.

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Text Reference

Service

SERVICE MENU

Diagnostic Events

DIAGNOSTIC EVENTS

OK

SRC 36 36 36

CODE 91-8 168-0 168-1

Engine ECM

OCC ACT 10 5 5

91-8

Throttle Pos Snsr Abnormal

Clr

OK

OK

OK

50 These illustrations show the information available within the Diagnostic Events menu. From the Service menu, use the appropriate arrow button to highlight the Diagnostic Events option and press the OK button to access the Diagnostic Events. Select the View Diagnostics display by pressing the OK button. The View Diagnostics option will display a complete list of codes (bottom left illustration). Each line on the list will show the following information: - SRC (Source ID) - CODE - OCC (Number of occurrences of the event or code) - ACT (if the code is active or inactive). Use the appropriate arrow button to highlight a diagnostic code or an event code on the list. Press the OK button to display the codes Detailed View (bottom right illustration). The Detailed View will display a text message that shows the following information: reporting ECM, failed component code, and explanation of the event.

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Text Reference

The technician can clear logged codes one at a time. Active codes are indicated with a mark under the "ACT" column. Active codes cannot be cleared until the faults have been corrected. To clear a code, access the Detailed View of the code, press the OK button and follow the prompts and directions. NOTE: Only Level I and Level II codes may be cleared with Messenger. When a code is cleared from Messenger, the memory from the reporting ECM is cleared. The code is not cleared from the Messenger ECM. Once the code has been cleared from the reporting ECM, Messenger will update the code list. Messenger is an interface between the technician and the machine ECMs.

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Text Reference

SERVICE MODE Main Menu Svc Mode Password OK

51

The Service Mode Password menu is used to enter the Service mode. The Service Mode Password protects certain features from access by the operator. Features that need to be protected from the operator can be enabled or disabled with a password. NOTE: For more information on the Messenger Monitoring System, refer to the 773F, 775F, 777F Off-highway Truck Monitoring Systems Operation, Troubleshooting, Testing, and Adjusting Service Manual module (RENR8344).

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Text Reference

1 2 3 4 5

52

Advisor/VIMS Display Shown above is the Advisor/VIMS graphical display module. It is located on the right side of the dash. It is the operator and technician’s interface with the Advisor Monitoring System, including VIMS. Information is displayed on a backlit LCD display screen. The top portion of the screen is called the "Top Banner" and it displays vital machine information at all times. The Top Banner may display different information from machine to machine, depending on the model and the attachments that are installed. At the right of the display screen is a column of five user interface buttons. These buttons are used to navigate through the numerous Advisor screens, to make menu selections, or to enter data. The five buttons, from top to bottom, are: - LEFT/UP Arrow Button (1) - This button is used for screen navigation or data entry. It can be used: • to scroll up a vertical list or scroll left across a horizontal list; • to decrease a setting value, such as decreasing brightness/contrast. - DOWN/RIGHT Arrow Button (2) - This button is also used for screen navigation or data entry. It can be used: • to scroll down a vertical list or scroll right across a horizontal list; • to increase a setting value, such as increasing brightness/contrast.

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Text Reference

- BACK Button (3) - This button is used: • to go up one level in a stair-step (hierarchical) menu structure, or to return to the previous screen; • as a backspace, or cancel key when the operator or technician wishes to delete entered characters. - HOME Button (4) - This button is used to return to the home menu screen, regardless of what screen is currently displayed. - OK Button (5) - This button is used: • to make selections from a screen; • to confirm an entry, such as a password, or for saving an operator profile entry. Navigation through the menus and sub-menus is accomplished by using the ARROW Buttons to highlight the desired selection, then pressing the OK Button. The ARROW Buttons are also used to highlight a mode or to set a parameter. Pressing the OK Button selects that option. NOTE: The left buttons are used to display a screen without scrolling. If a screen is selected and one of the left buttons is pressed and held for at least three seconds, the screen is saved (programmed). Whenever the button is pressed again the "saved" screen will appear.

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Text Reference

2612809V13

53 Copyright 2005 Caterpillar Inc. All Rights Reserved

P Normal

P

R

N

3

2

OK

1

03:55:46 07/7/2006 0%

Operator

54

Service Settings Payload

OK

Upon machine start-up (key ON), an introduction screen appears as shown in the top illustration and Advisor performs a self-test routine. After a few seconds the main screen will appear as shown in the bottom illustration. NOTE: The time and date is set with VIMSpc software. Also displayed to the right of the time and date is the inclinometer value.

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Text Reference

55

The illustration above shows a "pop-up" warning screen generated by the Transmission/Chassis ECM and reported by Advisor. There may be more warning screens if there are any other active faults or events reported to Advisor by the Transmission/Chassis ECM, or any other ECM on the machine. Advisor will scroll through all of the warning screens generated by all of the active faults and events. Each of these warning screens must be individually acknowledged by pressing the "OK" button. Each of these warning screens contains the following information: - The reporting ECM (in text) - The reporting MID (module identifier, or ECM code) - The ID (Component ID and Failure Mode Identifier) - A text message stating the failed component - A text message stating the failure mode of the component - A prompt for the operator to acknowledge the warning Acknowledging these warnings does not clear them from the reporting ECM's memory, but only clears them from the screen, or "snoozes" them. The warnings remain an active event or fault until the problem is resolved. Advisor will display the message again after a pre-determined amount of time, depending on the severity of the event.

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ADVISOR HOME MENU SELECTIONS

Text Reference

Operator

Service

Settings

Home Menu Screen

Payload

Monitor

Grade

Service Mode

56

Advisor’s menu structure is arranged in a stair-step, or hierarchical list format. When the operator or technician selects an option from a menu or list, the resulting screen is one level down from that selection. More selections, or options, may be available from that screen as well. There may also be more than one page of information or options to be displayed from any level. This is indicated by the "More Options" icon, which may point left, right, up, or down, depending upon how the data or list is arranged. The illustration above shows the options that are available from Advisor's Home Menu screen. The Home Menu screen and its options will be displayed upon pressing the HOME button from any screen within Advisor.

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P Normal

R

P

N

Text Reference

2

3

1

03:55:46 07/7/2006 0%

Operator Service

57

Settings Payload

P

P

R

N

OK

2

3

1

Operator Current Profile = Select Profile

Glen

View/Save Current

Press

Create Profile

to select a

Delete Profile

profile.

OK

58 OK

The Operator menu allows the user to perform the following: - Select a profile - Create a profile - Delete a profile - View/save a current profile - Factory Set (recalls default settings) The profile of an operator is a saved set of preferences that is identified by a name. Once the profile is created, the operator may associate various display settings and settings for the power train to that profile. After all of the parameters have been adjusted to the operator's preference, the operator may then save the parameters for future use.

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Text Reference

OPERATOR MENU SELECTION Units

Profile Name Selection Screen (Up to 10 Names)

Select Profile

Lights ON Dimming

View/Save Current

Operator

Language

Create Profile

Profile Name Creation Screen (Numbers/Letters)

Lights OFF Dimming

Delete Profile

Profile Name Deletion Screen (Up to 10 Names)

Contrast

Selects the Factory Default Settings

Factory Set

59

This illustration shows the options within the Operator Menu.

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P

R

P

N

Text Reference

3

2

1

03:55:46 07/7/2006 0%

Normal

Operator

60

Service Settings Payload

P

P

R

N

OK

3

2

1

Service Calibrations

Press

OK

61

System Information to enter the System Tests

calibrations

Service Parameters menu.

OK

The Service menu contains six submenus. The following is a list of the submenus: - Diagnostics - Calibrations - System Information - Tattletale - System Tests - Service Parameters

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Text Reference

SERVICE MENU

DIAGNOSTICS SUBMENU Active Events Logged Events Trigger Snapshot

Diagnostics

Data Logger Start Data Logger Reset

62

This illustration shows the diagnostics submenu within the service menu. The Active Events menu option shows the ECM and the service hours for each event. The following is a list of information that is displayed for the active event: - Electronic Control Module - Event Code - Date of occurrence - Time of occurrence - Warning Level - Number of occurrences The Logged Events menu option shows the list of events and diagnostic codes that have been recorded. Logged events can only be cleared by downloading and resetting the VIMS ECM with VIMSpc. The Trigger Snapshot menu option allows the user to manually initiate a snapshot of the system in addition to the snapshots that are already programmed. The snapshot will remain active until the time has elapsed.

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Text Reference

The Data Logger Start menu option allows the user to initiate the data logger. If the information for the data logger is being downloaded from the machine, the data logger cannot be started. The operator can initiate and stop the data logger numerous times until the total time for logging the data is thirty minutes. The Data Logger Reset menu option allows the user to reset the data logger, which clears all of the logged information. Thirty minutes will be available after the data logger has been reset. NOTE: The Data Logger is the only onboard file that can be reset through the Advisor display. The Advisor must be either in the Service Mode or Cat ET must be connected to the data link to reset the data logger. The VIMSpc software is not needed to reset the data logger.

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Text Reference

SERVICE MENU

SYSTEM INFORMATION SUBMENU

SERVICE MENU

Advisor

CALIBRATIONS SUBMENU

Engine

Truck Payload

System Information

Calibrations

Chassis

Brake

Inclinometer VIMS

SERVICE MENU

TATTLE TALE SUBMENU

SERVICE MENU

Active

SYSTEM TESTS SUBMENU

Brake Oil Temperature

Tattle Tale

Stall Diagnostic Test

Engine Coolant Temp

System Tests

Engine Speed

Self Test

Torque Converter Temp Fuel Level

63 These illustrations show four of the submenus within the service menu. The Calibrations option consists of the Truck Payload and Inclinometer calibrations. The System Information menu option allows the user to view the information for the following machine ECMs: - Advisor - Engine - Transmission/Chassis - Brake - VIMS The ECM information contains the following: - ECM serial number - Software part number - Software release date - Software description

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Text Reference

The following options are available under the tattletale menu: - Active - Brake Oil Temperature - Engine Coolant Temperature - Engine Speed - Torque Converter Temperature - Fuel Level The Active option will display the tattletale value for each gauge. The five specific options will display the tattletale value for the gauge that is specified. NOTE: The tattletale is password protected. The value for each gauge is protected from being cleared. The System Tests option will allow the technician to perform the Stall Diagnostic Test or the Self Test. The instrument cluster will initiate a self test when the key start switch is moved to the START position. The gauge needles will move to the maximum right position for 0.5 seconds and then return to the minimum left position. This action prevents the gauge needles from circling to the bottom side of the gauge if the display is inverted.

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Text Reference

SERVICE MENU

SERVICE PARAMETERS SUBMENU

Sort by ECM

Service Parameters

Sort by Type

All Parameters

64

This illustration shows the Service Parameters submenu within the service menu. The following Service Parameters options will be displayed: - Sort By ECM - Sort By Type - All parameters The Sort By ECM menu option allows the user to view the parameters that are associated with each ECM. All of the parameters for the specific ECM are listed. The following ECMs can be selected: - Advisor - Engine - Transmission/Chassis - Brake - VIMS

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Text Reference

The Sort By Type menu option allows the user to view the parameters that are associated with different components. The following types of parameters can be chosen: - Temperatures - Pressures - Speeds - Filter Switches - Operator Inputs - Sensor Duty Cycles - Totals The All Parameters menu option allows the user to view the entire list of parameters.

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P Normal

R

P

N

Text Reference

3

2

1

03:55:46 07/7/2006 0%

Operator

65

Service Settings Payload

P

P

R

N

OK

3

2

1

Settings Display Setup Machine Chassis

Press

OK

66

to enter the display setup menu.

OK

The Settings menu allows the user to view the parameters for the following the same as the Messenger Settings menu: - Display Setup - Machine - Transmission/Chassis - Brake - VIMS (same as Messenger Payload submenu) - Engine

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Text Reference

The Display Setup parameters relate to the operator’s preferences for the Advisor display. The following parameters may be adjusted: - Language (same as Messenger) - Units (same as Messenger) - Contrast (same as Messenger) - Headlights On (same as Messenger) - Headlights Off (same as Messenger) - Date format: (Advisor only) - Time format: (Advisor only) The Machine setting allows the user to set the machine serial number. The following parameters may be adjusted and are the same as the Messenger Display: - Product ID - Equipment ID The Transmission/Chassis setting allows the following parameters to be adjusted: - Top Gear Limit (same as Messenger) - Body Up Gear Limit (same as Messenger) - Machine Speed Limit (same as Messenger) - Fuel Economy Mode (same as Messenger) - Machine Overload Speed Limit (same as Messenger) - Load Count (Advisor only) The Brake setting is the same as the Messenger display. The VIMS/Payload menu allows the configuration of the Payload settings and is password protected. The following payload settings are the same as the Messenger Display: - Target Payload - Overload Limit - Green TPMS Lamp - Red TPMS Lamp - Last Pass Enabled The Engine setting allows the user to change the ether solenoid configuration to "No Ether Solenoid Installed" or "Continuous Flow" and is the same as the Messenger Display.

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P Normal

P

R

N

Text Reference

3

2

1

03:55:46 07/7/2006 0%

Service

67

Settings Payload Monitor

P

P

R

N

OK

3

2

1

Payload State: Loading Payload 90 T

Target 350 T

TON

68

OK

The Payload menu option is entered by selecting Payload from the Main menu. The Payload menu option allows the user to view the information for the payload. The user can view the following information: - Target for the payload - Calculated gauge for the payload

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P Normal

R

P

N

Text Reference

3

2

1

03:55:46 07/7/2006 0%

Service

69

Settings Payload Monitor

OK

Monitor: Parameter Screen 1 Brake Oil Temperature 45 C

Torque Converter Temperature 37 C

70 Boost Pressure

Atmospheric Pressure 20 kPa

23 kPa

OK

The Monitor menu option allows the user to view four parameters. The navigation button is used to select the parameter or view a different parameter. Press the OK button to obtain a list of available parameters.

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P Normal

P

R

N

Text Reference

3

2

1

03:55:46 07/7/2006 0%

Settings

71

Payload Monitor Grade

P

P

R

N

OK

3

2 30

% GRADE

1 20 10

00

72

0 -30 -10

-20

OK

The Grade menu option allows the user to view the grade of the hill. The user can view the following information: - Percentage of the grade value - Image of the truck that represents the grade

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P Normal

P

R

N

Text Reference

3

2

1

03:55:46 07/7/2006 0%

Payload

73

Monitor Grade Service Mode

P

P

R

N

3

2

OK

1

Service Mode Service Mode: Disabled

74

Press OK to Enable

OK

The Service Mode menu option allows the user to enable and disable the service mode. The password entry screen will appear if the password has been entered in Cat ET. The Advisor will enter the service mode after the password has been entered correctly. NOTE: For more information on the Advisor/VIMS Monitoring System, refer to the 773F, 775F, 777F Off-highway Truck Vital Information Management System (VIMS) Systems Operation, Troubleshooting, Testing, and Adjusting Service Manual module (KENR5955).

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Text Reference

75

ENGINE Shown is the C32 engine with ACERT™ Technology used in the 777F Off-highway Truck. The engine performance specifications for the 777F Truck are: - Serial No. Prefix: LJW - Performance spec: 0K5981 - Gross power: 758 kW (1016 hp) - Full load rpm: 1750 - High idle rpm: 1938 ± 10 - Low idle rpm: 650 - Overspeed rpm: 2800 This V-12 engine uses twin turbochargers, Air to Air AfterCooler (ATAAC) and Mechanical Electronic Unit Injection (MEUI) for power, reliability, and fuel economy. The C32 is compliant with U.S. EPA Tier 2 and European Union Stage II emissions regulations.

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Text Reference

CAT Data Link

ENGINE ECM SYSTEM DIAGRAM

MEUI Injectors (12) 7E6513 ORS Solenoid (attachment) Left Bank (Odd) Engine Retarder Solenoids 066-8391 (Connector PN)

Ether Start Relay

Right Bank (Even) Engine Retarder Solenoids 066-8391 (Connector PN) Outputs Inputs

Rockford Fan Solenoid ( At t achment )

Speed Sensor No. 1 (Crank)

Outputs Inputs

Key Start Switch

Speed Sensor No. 2 (Cam) Timing Cal Probe Connector

Throttle Pedal Position Sensor

Right Intake Manifold Temperature Sensor

Back-up Throttle Switch

Left Intake Manifold Temperature Sensor

ORS Level Relay ( at t achment )

Coolant Temperature Sensor Right Turbo Outlet Pressure Sensor

Ground Level Shutdown Switch

Left Turbo Outlet Pressure Sensor

Rockford Fan Speed Sensor (Attachment)

Engine Oil Pressure

Left Air Filter Restriction (Turbo Inlet Left)

Atmospheric Pressure

Right Air Filter Restriction (Turbo Inlet Right)

Exhaust Temperature Sensors (4)

Air Conditioning Status

Oil Level Switch Fuel Temp Sensor Fuel Pressure Sensor Differential Fuel Pressure Switch

J1 (MACHINE) CONNECTOR

J2 (ENGINE) CONNECTOR

76

Engine Electronic Control System Shown is the electronic control system component diagram for the C32 engine used in the 777F Truck. Fuel injection is controlled by the Engine Electronic Control Module (ECM). Many electronic signals are sent to the Engine ECM by sensors, switches, and senders. The Engine ECM analyzes these signals and sends signals to various output components. Output components can be relays, lamps, other controls, or solenoids. For example, based on the various input signals, the Engine ECM determines when and for how long to energize the injector solenoids. When the injector solenoids are energized determines the timing of the engine. How long the solenoids are energized determines the engine speed.

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Text Reference

3

2

1

77

Fuel injection and some other systems are controlled by the Engine ECM (1) located at the front of the engine. Other systems controlled by the Engine ECM are: ether injection, engine start function, engine oil pre-lubrication, variable speed Rockford fan, engine retarding, and engine derate. The Engine ECM has two main connectors for diagnostics. The larger 120-pin connector (2) known as J2 connects to the engine harness. The smaller 70-pin connector (3) is identified on schematics as J1 and connects to the machine harness. A 2-pin timing calibration connector is located to the right of the ECM. If the engine requires timing calibration, a timing calibration sensor (magnetic pickup) is installed in the flywheel housing and connected to the timing calibration connector. Using the Caterpillar ET (Cat ET) service tool, timing calibration is performed automatically for the speed/timing sensors. This step is performed to avoid instability and ensures that no backlash is present in the timing gears during the calibration process. Timing calibration improves fuel injection accuracy by correcting for any slight tolerances between the crankshaft, timing gears, and timing wheel. Timing calibration is normally performed after ECM replacement, cam or crank sensor replacement, or timing wheel replacement. Occasionally, Caterpillar will make changes to the internal software that controls the performance of the engine. These changes can be performed by using the WinFlash program in Cat ET. Cat ET is used to diagnose and program the electronic controls used in Off-highway Trucks. If using the WinFlash program, a "flash" file must be obtained from Caterpillar and uploaded to the ECM.

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Text Reference

3

4 1

2

6 5

78

The left intake air temperature sensor (1) and right intake air temperature sensor (2) are located on top of the engine. The intake air temperature sensors produce an analog signal that is monitored by the Engine ECM. The ECM monitors intake air temperature for derating the engine at high temperatures, for engine shutdown at high temperatures, and for signaling the monitoring system in the event of a problem. NOTE: If a high temperature event is severe enough, the monitoring system will issue a Level 3 warning. The operator must park the machine as soon as possible. When the Engine ECM determines that the ground speed is zero and the transmission is in PARK, the engine will automatically shut down. The coolant temperature sensor (3) is located on top of the engine toward the front left side. The coolant temperature sensor is an analog sensor that is monitored by the Engine ECM. When the coolant temperature is too high, the Engine ECM will signal the monitoring system to display a warning. The Engine ECM also uses the coolant temperature sensor information for cold mode functions such as timing changes, elevated idle, cold cylinder cut-out, and ether injection. The left turbo outlet pressure sensor (4) and right turbo outlet pressure sensor (5) are used for calculating boost. The atmospheric pressure sensor (6) is located on top of the engine toward the front right side. The atmospheric pressure sensor is an analog sensor that is monitored by the Engine ECM. The ECM monitors atmospheric pressure for the following: altitude derate, air inlet restriction derate, and calibration reference for other sensors.

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Text Reference

2

1 3

79 The crankshaft speed/timing sensor (1) is located on the lower left of the engine toward the front side. The crank sensor measures engine speed and timing for control of the timing and delivery of fuel to each of the engine's cylinders. Sensing engine speed allows engine speed governing, fuel limiting, and fuel injection timing. If the crank speed/timing sensor fails, the cam speed/timing sensor allows for continuous operation. The oil pressure sensor (2) is located on the left side of the engine. The oil pressure sensor is an analog sensor that is monitored by the Engine ECM. When the oil pressure is too low, the Engine ECM will signal the monitoring system to display a warning. The ECM will also log an event that requires a factory password to clear. The oil level switch (3) monitors the oil level in the pan. The C32 engine in the 777F Truck can be equipped with an optional Oil Renewal System (ORS). The ORS increases the oil change interval and decreases the amount of used oil in need of disposal. The life of the engine is not shortened and the availability of the machine is increased. The ORS meters engine oil that has been filtered into the fuel supply. The metered oil is consumed in the engine during the normal combustion process. The Engine ECM controls the amount of oil that is metered based on the actual load factor or on the fuel that is consumed by the engine. Whenever the old oil from the oil pan is injected into the return fuel line, new oil from a makeup tank is added to the oil pan. Regular additions of new oil will allow the oil change level to be extended. Reviewing the reports of the S•O•S Oil Analysis will determine if a problem has occurred and if the oil needs to be changed.

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Text Reference

80

The cam speed/timing sensor (arrow) is located on the right side of the engine in the rear of the timing gear housing behind the primary fuel filter. The cam sensor is used as a back-up for the crank speed/timing sensor. If the crank speed/timing sensor fails, the cam speed/timing sensor allows for continuous operation.

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Text Reference

LOSS OF ENGINE SPEED/TIMING SIGNAL - Engine will start and run with one speed/timing sensor signal - Engine will NOT start or run without at least one speed/timing sensor signal - If crank sensor fails during engine operation: - Slight change in engine performance - If crank sensor signal is not present at engine start up: - Engine starts normally - If cam sensor fails during engine operation: - No noticeable change in engine performance - If cam sensor signal is not present at engine start up: - Engine will start with crank sensor signal, but may take longer to start and run rough for a few seconds

81

The engine will start and run when only one sensor signal is present from either the crank or cam sensor. During engine operation, if both speed/timing sensors fail, the Engine ECM will stop fuel injection and the engine will shut down. During start-up, the loss of both sensors will prevent the engine from starting. If the engine is running and the signal from the crank speed/timing sensor is lost, a slight change in engine performance will be noticed when the Engine ECM performs the changeover to the cam speed/timing sensor. If the signal from the crank speed/timing sensor is not present during start up, the engine will start normally. Loss of the cam speed/timing sensor during engine operation will not result in any noticeable change in engine performance. However, if the signal from the cam speed/timing sensor is not present during start up, the engine may require a slightly longer period of time to start and may run rough for a few seconds until the ECM determines the proper firing order by using only the crank engine speed/timing sensor.

SERV1828 01/07

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Text Reference

The teeth configuration in the crankshaft timing wheel are not the same as the camshaft timing wheel. The camshaft timing wheel includes 37 timing teeth with 36 of the teeth spaced equally at 10° apart. One tooth is spaced 5° apart from the other teeth. There are only 35 teeth on the crankshaft gear spaced equally at 10° apart. Two of the teeth are spaced at 20° apart, which creates a "gap" in the gear teeth. When the Engine ECM uses the cam speed sensor to determine timing for engine starting, the ECM knows exactly what cylinder is at TDC. The following cylinders are at TDC at the same time (one cylinder bank only): - Cylinder No. 1 (compression stroke) and No. 6 (exhaust stroke) - Cylinder No. 2 (compression stroke) and No. 5 (exhaust stroke) - Cylinder No. 3 (compression stroke) and No. 4 (exhaust stroke) When the Engine ECM uses the crank speed sensor to determine timing for engine starting, the ECM does not know which of the two cylinders is at TDC. As an example, the Engine ECM will attempt to fire Cylinder No. 1 and check if there is any increase in the engine RPM. If there is no increase in rpm, the ECM determines that the TDC timing position at that firing moment is Cylinder No. 6. This action may result in a longer engine start time.

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Text Reference

82

Located behind the right pedal, the throttle position sensor (arrow) provides the desired throttle position to the Engine ECM. If the Engine ECM detects a fault in the throttle position sensor, the throttle back-up switch in the cab can be used to increase the engine speed to 1300 rpm. The throttle position sensor receives a regulated 8.0 ± 0.5 Volts from the Engine ECM. The throttle position sensor output signal is a Pulse Width Modulated (PWM) signal that varies with throttle position and is expressed as a percentage between 0 and 100%. To check the output signal of the throttle position sensor, connect a multimeter between Pins B and C of the throttle position sensor connector. Set the meter to read "Duty Cycle." The duty cycle output of the throttle position sensor should be: - Low Idle: 16 ± 6% - High Idle: 85 ± 4%

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Text Reference

2

1

83

The pre-lubrication (QuickEvac) pump (1) is located on the end of the secondary steering/brake release pump and motor assembly (2). The pump and motor assembly is now located on the front of the front frame crossmember. The engine oil pre-lubrication QuickEvac pump is controlled by the Transmission/Chassis ECM. The Transmission/Chassis ECM energizes the pre-lubrication pump relay located behind the cab. The relay behind the cab then energizes the pre-lube relay on the left frame. The QuickEvac mode is used to allow the technician to quickly evacuate the oil for an oil change. The QuickEvac mode can only be performed when the engine lockout is activated. Engine starting and pre-lubrication functions are also inhibited when the engine lockout is activated.

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Text Reference

84

If the truck is equipped with an ether start system, the Engine ECM will automatically inject ether from the ether valve (arrow) and ether cylinder during cranking. The amount of automatic ether injection depends on the engine oil or jacket water coolant temperature. The Engine ECM sends a duty cycle signal to the ether injection relay. The maximum duty cycle is 50%. A 50% duty cycle will pulse the ether relay ON three seconds and OFF three seconds. The maximum ether delivery is ten 3-second shots per minute. Each shot delivers 6 ml (0.2 oz) of ether. The Engine ECM will energize the ether injection relay only if: - Engine intake manifold air temperature is below a certain temperature. - Engine coolant temperature is below a certain temperature. Cat ET can be connected to the machine to turn the ether injection system ON or OFF.

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Text Reference

HIGH COOLANT TEMPERATURE DERATE 120%

% Derate

100% 80% 60% 40% 20% 0% 110 C 230 F

111 232

111.5 233

112 234

112.5 235

113 235.5

113.5 236.5

114 237

114.5 238

Coolant Temperature Level 1 Warning

Level 2 Warning/ Derat es

85

Engine Derates The coolant temperature sensor measures the temperature of the coolant. When the temperature of the coolant exceeds 110° C (230° F), the Engine ECM will initiate a Level 1 Warning. When the temperature of the coolant exceeds 111° C (231° F), the Engine ECM will initiate a Level 2 Warning. At 111° C (231° F) the Engine ECM will initiate a 25% derate. Refer to the illustration for the remainder of the high engine coolant temperature derates. At 100% derate, the engine available power will be approximately 50%.

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Text Reference

C11-C32 ENGINE INTAKE MANIFOLD TEMPERATURE DERATE 21% 18%

% Derate

15% 12% 9% 6% 3% 0% C F

82 180

86 187

87 189

88 190

89 192

90 194

91 196

92 198

93 199

Intake Manifold Temperature Level 1 Warning

Level 2 Warning / Derat es

86

The intake manifold air temperature sensor measures the temperature of the air that is flowing to the intake manifold. The sensor is used to initiate warning levels and engine derates. After the engine is running for at least 3 minutes and if the intake manifold air temperature goes above 82° C (180° F), the Engine ECM will initiate a Level 1 Warning. After the engine is running for at least 3 minutes and if the intake manifold air temperature goes above 86° C (187° F), the Engine ECM will initiate a Level 2 Warning. With the Level 2 Warning, the Engine ECM signals the engine to initiate a 3% derate. This derate will have a 20% upper limit.

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Text Reference

ENGINE EXHAUST MANIFOLD TEMPERATURE DERATE 70% 60%

% Derate

50% 40% 30% 20% 10% 0% C F

760 1400

805 1481

810 1490

815 1499

820 1508

825 1517

830 1526

835 1535

840 1544

Exhaust Manifold Temperature Level 1 Warning

Level 2 Warning / Derat es

87

The exhaust temperature sensors measure the temperature of the exhaust air flowing out of the exhaust manifolds. The sensors are used to initiate warning levels and engine derates. After the engine is running for over 4 minutes and if the exhaust manifold air temperature goes above 760° C (1400° F), the Engine ECM will initiate a Level 1 Warning. After the engine is running for over 4 minutes and if the exhaust manifold air temperature goes above 805° C (1481° F), the Engine ECM will initiate a Level 2 Warning. With the Level 2 Warning, the Engine ECM signals the engine to initiate a derate. This derate will have a 75% upper limit.

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Text Reference

LOW OIL PRESSURE

psi kPa 26.0 180 23.0 160 20.0 140

Oil Pressure

17.0 120 15.0 100 12.0 80 9.0

60

6.0

40

3.0

20

0

0

35% Derate

0

500

1000

1500

2000

2340

Engine rpm kPa Warning Level 1

kPa Shut down Level 3

88

This illustration shows a graph with the two different warning levels for low oil pressure and the low oil pressure derate. When the oil pressure is below the blue line (154 kPa @ 1600 rpm) (22 psi @ 1600 rpm), the Engine ECM will enable the low oil pressure Level 1 Warning. Change machine operation or perform maintenance to the system in the event of a warning. When the oil pressure is below the red line (104 kPa @ 1600 rpm)(15 psi @ 1600 rpm), the Engine ECM will enable the low oil pressure Level 3 Warning. The operator should immediately perform a safe engine shutdown in the event of a Level 3 warning. Also, with the Level 3 Warning the Engine ECM initiates a 35% engine derate. If the signal between the Engine ECM and the oil pressure sensor is lost or disabled, the Engine ECM will initiate a low engine oil pressure Level 1 Warning.

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Text Reference

AIR INLET RESTRICTION DERATE 16% 14%

% Derate

12% 10% 8% 6% 4% 2% 0% kPa 0 psi 0

2 0.3

4 0.6

6 0.9

8 1.2

10 1.5

12 1.7

14 2.0

16 2.3

Air Restriction Difference Level 1 Warning

Level 2 Warning/ Derat es

89

The air inlet restriction is the pressure difference between the turbo inlet pressure sensor and the atmospheric sensor. The turbo inlet pressure sensor measures the air inlet pressure at the turbocharger compressor housing. As the air restriction increases, the pressure difference will increase. If the engine has been running for over 4 minutes and the air inlet restriction is 7.5 kPa (30 in. of water) for 30 seconds, the Engine ECM will initiate a Level 1 Warning. If the air restriction increases to 9.0 kPa (36 in. of water) for 30 seconds or the turbo inlet pressure sensor fails, then a Level 2 Warning will occur and the engine will enter the air inlet restriction derate. When the pressure difference between the turbo inlet pressure sensor and the atmospheric sensor reach a difference of 10.0 kPa (40 in. of water), the Engine ECM will derate the engine approximately 2%. The Engine ECM will then derate the engine 2% more for every 1 kPa (2 in. of water) difference up to 20%.

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Text Reference

FUEL TEMPERATURE DERATE 30%

% Derate

25% 20% 15% 10% 5%

0% 90.2

90.4

90.6

92.2

C

89.8 90.0

91.0

91.2

91.4

91.6

91.8

92.0

F

193.6 194.0 194.4 194.7 195.0 195.4 195.8

196.2

196.5

196.9

197.2

197.6 198.0

90.8

Fuel Temperature Level 1 Warning

Level 2 Warning / Derates

90

This illustration shows the graph for the warning and the derates map for the fuel temperature. When the fuel temperature exceeds 90° C (194° F), the Engine ECM will activate a Level 1 Warning. When the fuel temperature increases to 91.0° (196° F) a Level 2 Warning will be initiated by the Engine ECM. At the same time, the engine will derate to 12.5%. If the fuel temperature exceeds 92° C (198° F), the engine will be derated to 25%. A fuel temperature sensor open circuit will derate the engine to 12.5%. Excessive fuel temperature will cause injector wear.

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Text Reference

FUEL FILTER RESTRICTION DERATE FUEL TEMP ABOVE 30° C (86° F) AND FUEL PRESSURE ABOVE 138 kPa (20 psi)

60%

% Derate

50% 40% 30% 20% 10% 0% 0

3 min

1 hr

2 hr

3 hr

4 hr

5 hr

6hr

Time Level 1Warning

Level 2 Warning/Derates

91

When the differential pressure switch recognizes a fuel pressure of 138 kPa (20 psi) for 1 hour, the Engine ECM will initiate a Level 1 Warning. When the differential pressure switch recognizes 138 kPa (20 psi) across the filter for 4 hours, the Engine ECM will initiate a Level 2 Warning. With the Level 2 Warning initiated, a 35 % derate is applied to the engine. This feature will be disabled when the fuel temperature is below 30° C (86° F).

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Text Reference

3 1

2

92

Engine Compression Brake The 777F Truck can be equipped with the optional engine compression brake. The compression brake provides higher downhill travel speeds and reduces brake wear in addition to the Automatic Retarder Control (ARC) system. The compression brake uses a master/slave hydraulic actuation system to open exhaust valves on the compression stroke which releases pressurized air and creates a net braking force at the flywheel. The compression brake assembly, as shown in this illustration, controls two cylinders. The compression brake assembly is mounted to the rocker arm shaft supports below the engine valve covers. The compression brake is pressurized with engine oil from the rocker arm shaft and uses a solenoid valve to control oil flow in the brake housing. The compression brake is activated by a signal from the Engine ECM to the solenoid valve (1). As the fuel injector rocker arm pushes up on the master piston (2), the corresponding slave piston (3) is pressurized to push down on the exhaust valve bridge, decompressing the cylinder and preventing the normal power stroke. On the C32 engine, up to six brake assemblies are used. The control circuit for the compression brake permits the operation of either two, four, or all six of the compression brake assemblies which provides progressive braking capabilities with the retarding effect of four, eight, or all 12 of the engine cylinders. Compression brake system service consists of only periodic valve lash checks.

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Text Reference

ENGINE COMPRESSION BRAKE HYDRAULIC CIRCUIT COMPRESSION BRAKE OFF Slave Piston Check Valve To Slave Piston and Master Cylinder

Exhaust Valve Rocker Arm

Compression Brake Solenoid Valve

Fuel Injector Rocker Arm

Rocker Arm Shaft Oil Passage Engine Oil Pump

Master Piston

Exhaust Valve

93

This illustration shows the oil flow in the C32 engine compression brake. Oil from the engine oil pump flows through the rocker arm shaft oil passage. The compression brake solenoid valve controls the oil flow in the compression brake hydraulic circuit. When the Engine ECM energizes the solenoid, oil flows through the check valves to the slave pistons and the master pistons. Oil pressure overcomes spring force and the master piston moves down and contacts the fuel injector rocker arm. The master piston will follow the movement of the fuel injector rocker arm. As the fuel injector rocker arm moves up the master piston moves up and causes the oil to close the check valve. With the check valve closed, oil pressure increases in the compression brake hydraulic circuit and the slave piston is forced down. The slave piston makes contact with the exhaust valve rocker arm and causes the exhaust valve to open. As the exhaust valve opens, the engine cylinder pressure is relieved through the open exhaust valve, which creates a net braking force at the flywheel.

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Text Reference

When the fuel injector rocker arm moves down, the master piston moves down and the hydraulic pressure decreases. The exhaust valves are returned to the closed position by the exhaust rocker arm. The check valve opens and relieves the oil pressure. When the Engine ECM de-energizes the compression brake solenoid, oil is drained from the slave and master pistons to the tank. The exhaust valves close and the slave piston returns to the starting position.

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Text Reference

ENGINE COMPRESSION BRAKE SCHEMATIC

Left Bank Valve Cover Entry Connector Compression Brake Solenoid 1 and 3

Compression Brake Solenoid 9 and 11

Compression Brake Solenoid 5 and 7

10 11 12

J700-BR J701-GN K739-BU

P2/J2

Engine ECM

5 3 14

Compression Brake Med / Hi Compression Brake Low / Hi Compression Brake Return

8 1

Compression Brake Med / Hi Compression Brake Low / Hi

Right Bank Valve Cover Entry Connector Compression Brake Solenoid 10 and 12

Compression Brake Solenoid 2 and 4

Compression Brake Solenoid 6 and 8

10 11 12

K737-BR K738-GN K739-BU 892-BR 893-GN

P1/J1 9 Cat Data Link 8 Cat Data Link +

P1/J1 893-GN 892-BR 772-BR A235-BK

Compression Brake Enable Switch

10 20 34 45

Brake ECM Cat Data Link + Cat Data Link Compression Brake Enable Sensor Return

94

This illustration shows the wiring and components of the engine compression brake. When the compression brake switch in the cab is activated, the Brake ECM sends a signal to the Engine ECM via the Cat Data Link. The Engine ECM controls the compression brake solenoids to slow the machine. The Engine ECM provides three levels of braking: LOW, MEDIUM, and HIGH. When the ECM commands a LOW braking level, two solenoids (one on each valve bank) will activate the compression brake for four cylinders (5, 7, 6, and 8). When the ECM commands a MEDIUM braking level, four solenoids (two on each valve bank) will activate the compression brake for eight cylinders (5, 7, 6, 8, 9, 11, 2, and 4). When the ECM commands a HIGH braking level, six solenoids (three on each valve bank) will activate the compression brake for all 12 cylinders.

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Text Reference

ARC POWER AND COMPRESSION BRAKING LEVELS VS TIME Enough Instantaneous braking power available to Allow 1/3 Compression on. (ARC Power-offset) Leaves enough brake power for 1/3 compression braking. ARC brake power should drop by equivalent amount.

ARC ramps up current, ARC braking power also increases. Total braking power = ARC brake power only

900000

800000

Braking Power (Watts)

ARC power dropped enough that we don't have compression braking at all.

600000

Not enough pow er to keep comp enabled. Disable CB

Total brake Total brake power Total brake power = ARC = ARC brake power power = ARC brake power + 1/3 compression brake power + 2/3 comp brake

Total brake power = ARC brake power + 1/3 comp brake power

700000

ARC power began to drop enough that we had to lose 1/3 compression power.

Total brake ARC brake 0 ARC shut Off

2/3

500000

400000

1/3

1/3

300000 200000 100000 0 0

5

10

15

20

25

30

35

40

45

50

55

60

Time (Seconds)

95

This chart shows an example of the ARC and engine compression brake levels in a one minute period during a drive cycle. When the machine speed exceeds a pre-determined speed, the ARC system is activated to slow the machine. If further braking is required, the Engine ECM will command the engine compression brake to the LOW, MEDIUM, or HIGH brake level setting as necessary to slow the machine.

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Text Reference

1

3

2

96

Cooling System The jacket water cooling system on the 777F uses a Next Generation Modular Radiator (NGMR). The NGMR (1) is a single-pass flow design, replacing the two-pass flow folded core system. The coolant enters at the top left and flows out at the bottom right, similar to an automotive design. Being modular, individual cores may be removed for service while the radiator remains in place. The aftercooler cooling system in the 777F Trucks is now an ATAAC system. The ATAAC cores (2) are located in front of the radiator. Intake air is cooled after being compressed by the turbocharger before being routed to the engine combustion chamber. Also visible in this illustration is the air conditioning condenser (3).

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Text Reference

6 5 2

97 1 4 3

COOLING SYSTEM FLOW Thermostat Housing

Radiator

Engine Block

ATAAC

98

Brake Oil Cooler

Brake Oil Cooler

Transmission Oil Cooler

Engine Oil Cooler Water Pump

Jacket water coolant flows from the water pump (1) through the engine oil cooler (2), through the two brake oil coolers (3), and the transmission oil cooler (4) to both sides of the engine cylinder block. Coolant flows through the engine block to the cylinder heads. From the cylinder heads, the coolant flows to the two temperature regulators and, based on coolant temperature, either flows to the radiator (if hot) or through the bypass tube (5) to the water pump (if cold) to recirculate until the engine reaches operating temperature. The thermostats are located in the thermostat housing (6) at the top of the bypass tube. The bottom illustration shows a schematic of the coolant flow.

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Text Reference

ENGINE OIL SYSTEM Engine Block

Engine Oil Filters

Bypass Valve Engine Oil Cooler

Engine Oil Pump

99

Lubrication System The engine oil pump draws oil from the oil pan through a screen. Oil flows from the pump through an engine oil cooler bypass valve to the engine oil cooler. The bypass valve for the engine oil cooler permits oil flow to the system during cold starts when the oil is thick or if the cooler is plugged. Oil flows from the engine oil cooler to the oil filters. The oil flows through the filters and enters the engine cylinder block to clean, cool, and lubricate the internal components and the turbochargers.

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Text Reference

100

Fuel System The fuel tank is located on the right side of the truck. Fuel is pulled from the tank through the primary fuel filter by the fuel transfer pump. Priming is now done electrically using a switch (arrow) located above the primary fuel filter. A reusable fuel/water separator mounts directly to the bottom of the fuel filter.

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Text Reference

101

The fuel transfer pump (arrow) is located at the top rear of the engine. The fuel transfer pump contains a bypass valve to protect the fuel system components from excessive pressure. The bypass valve setting is higher than the setting of the fuel pressure regulator. Fuel flows from the transfer pump to the secondary fuel filter located on the right side of the engine.

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Text Reference

2 3

1

102

The differential fuel pressure switch (1) is located in the top of the secondary fuel filter housing on the right side of the engine. This switch will indicate a restriction in the fuel filter. A warning will be sent by the Engine ECM to the monitoring system. The fuel pressure sensor (2) is located in the top of the secondary fuel filter housing, directly behind the differential pressure switch. This sensor is used to monitor fuel pressure. The engine fuel temperature sensor (3) is located in the top of the secondary fuel filter housing, behind the other two sensors. The Engine ECM uses the fuel temperature measurement to make corrections to the fuel rate and maintain power regardless of fuel temperature (within certain parameters). This feature is called "Fuel Temperature Compensation."

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Text Reference

1

2

103

Fuel flows from the fuel filter base through the steel tubes (1) to the MEUI fuel injectors. Return fuel from the injectors flows through the fuel pressure regulator (2) before returning to the fuel tank. Fuel pressure is controlled by the fuel pressure regulator. Fuel pressure should be between 420 and 840 kPa (61 and 122 psi) at Full Load rpm.

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Text Reference

LOW PRESSURE FUEL SYSTEM

Fuel Priming Pump

Fuel Pressure Regulator

Primary Fuel Filter Fuel Tank

Fuel Transfer Pump

Secondary Fuel Filter

Cylinder Head

Cylinder Head

104

Fuel is pulled from the tank through the primary fuel filter by the fuel transfer pump. Fuel flows from the transfer pump to the secondary fuel filter. Fuel flows from the secondary fuel filter base through the fuel injectors in the cylinder heads. Return fuel from the injectors flows through the fuel pressure regulator before returning to the tank. The electric fuel priming pump is used to fill the filters after they are changed.

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Text Reference

105

When an injector is replaced, the injector trim codes must be retrieved and installed in the Engine ECM. The trim code files are located on a CD that comes with the new injector or can be obtained from the Service Information System (SIS). Access the trim code files from the Cat ET Service menu as shown in the illustration.

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Text Reference

106

Select the injector trim file from either the CD or from the appropriate directory on the computer if the trim file was obtained from SIS.

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Text Reference

2

3 1

107

Air Intake and Exhaust System Shown are the air intake system components. Check the air filter restriction indicator (1). If the yellow piston is in the red zone, the air filters are restricted and must be serviced. The air filter housing covers serve as the precleaner assemblies. When servicing the filter elements, clean the precleaners (2) and dust valves (3) using air or water pressure, or detergent wash. The dust valve is OPEN when the engine is OFF and closes when the engine is running. The dust valve must be flexible and closed when the engine is running or the precleaner will not function properly and the air filters will have a shortened life. Two filter elements are installed in the filter housings. The large element is the primary element and the small element is the secondary element. Air intake system tips: - The primary element can be cleaned a maximum of six times. - Never clean the secondary element for reuse. Always replace the secondary element. - Air filter restriction causes black exhaust smoke and low power.

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Text Reference

108

There is a turbocharger inlet pressure sensor (arrow) located in the tube between the air filters and the turbochargers. This illustration shows one of the inlet pressure sensors. The Engine ECM uses the turbocharger inlet pressure sensor in combination with the atmospheric pressure sensor to determine air filter restriction. The ECM provides the input signal to the monitoring system, which informs the operator of the air filter restriction. As the air restriction increases, the pressure difference will increase. If the engine has been running for over 4 minutes and the air inlet restriction is 7.5 kPa (30 in. of water) for 30 seconds, the Engine ECM will initiate a Level 1 Warning. If the air restriction increases to 9.0 kPa (36 in. of water) for 30 seconds or the turbo inlet pressure sensor fails, then a Level 2 Warning will occur and the engine will enter the air inlet restriction derate. When the pressure difference between the turbo inlet pressure sensor and the atmospheric sensor reach a difference of 10.0 kPa (40 in. of water), the Engine ECM will derate the engine approximately 2%. The Engine ECM will then derate the engine 2% more for every 1 kPa (2 in. of water) difference up to 20%.

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Text Reference

1

2

109

The C32 engine is equipped with two turbochargers, one on each side. Each turbocharger is driven by the exhaust gas from the cylinders which enters the turbine side (1) of the turbocharger from the exhaust manifold. The exhaust gas flows through the turbocharger, spinning the turbine wheel, then exits to the exhaust piping and muffler. The clean air from the filters enters the compressor side (2) of the turbocharger where it is compressed by the spinning turbine and picks up heat. The compressed air from the turbocharger then flows out the top of the turbocharger to the aftercooler. After the air is cooled by the aftercooler, the air flows to the cylinders and combines with the fuel for combustion.

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Text Reference

110

The compressed air that was heated at the turbochargers is routed through finned Air to Air AfterCooler (ATAAC) cores (arrows) mounted in front of the radiator. Outside air passes through the ATAAC cores and the radiator to cool both the intake air and the engine coolant. The cooled, compressed air exits the aftercoolers and is piped to the intake manifolds.

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Text Reference

111

Two exhaust temperature sensors (arrows) are located in each exhaust manifold. The exhaust temperature sensors send a signal to the Engine ECM indicating exhaust temperature. When the engine runs at low idle, the temperature of an exhaust manifold port can indicate the condition of a fuel injection nozzle. A low temperature indicates that no fuel is flowing to the cylinder. An inoperative fuel injection nozzle or a problem with the fuel injection pump could cause this low temperature. A very high temperature can indicate that too much fuel is flowing to the cylinder. A malfunctioning fuel injection nozzle, plugged air filters, or a restriction in the turbochargers or the muffler could cause this very high temperature.

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Text Reference

1 2

112

Shown are the turbocharger outlet pressure sensors (1). The turbocharger outlet pressure sensors send an input signal to the Engine ECM. The Engine ECM compares the value of the turbo outlet pressure sensor with the value of the atmospheric pressure sensor (2) and calculates boost pressure. The best way to check for a power problem is to compare the truck performance with the rimpull charts in the Caterpillar Performance Handbook or the 777F Specalog. The truck should be able to climb a grade in the same gear as specified in these two publications. If an engine power problem is suspected, check boost pressure at full load rpm. If boost pressure is correct at full load rpm, the engine is not the problem and other systems such as the torque converter should be checked. To check boost pressure at full load rpm, the truck must be operated in FIRST GEAR with the throttle at MAXIMUM and the retarder gradually engaged. Traveling up a grade is best as long as the engine rpm does not fall below the full load rpm specification during the test. Gradually engage the retarder until the full load rpm is displayed. When the full load rpm is displayed, record the boost pressure. If boost pressure is within the specifications at full load rpm, the engine is operating correctly. NOTE: The monitoring system includes a transmission stall test that can be used to check boost at full load. Cat ET should be used to view the status while running the transmission stall test.

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Text Reference

Use Cat ET or the monitoring system display panel to view the engine rpm and boost pressure. Generally, Torque Converter (TC) stall speed (in gear, full throttle, zero ground speed) is used to determine if the engine power is low or a torque converter problem exists. For example, if the engine power is within specification and the stall speed is high, the torque converter may have a problem (low internal oil pressure, poor internal tolerances or damaged components). NOTE: The 777F has a torque limiting function and engine speed is always limited to 1831 rpm during the stall test.

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Text Reference

From Air Filters

AIR INDUCTION AND EXHAUST SYSTEM

Muffler

ATAAC

From Air Filters

113

This schematic shows the flow through the air induction and exhaust system. The turbochargers are driven by the exhaust gas from the cylinders which enters the turbine side of the turbochargers. The exhaust gas flows through the turbochargers, the exhaust piping, and the mufflers. The clean air from the filters enters the compressor side of the turbochargers. The compressed air from the turbochargers flows to the ATAAC. After the air is cooled by the ATAAC, the air flows to the cylinders and combines with the fuel for combustion.

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5

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Text Reference

9

6

8 7 3

1 2

4

114

POWER TRAIN The 777F Off-highway Truck power train is electronically controlled. The Transmission/Chassis ECM controls the ECPC transmission shifting and the torque converter lockup clutch operation. The transmission has seven forward speeds and one reverse speed. Power flows from the engine to the rear wheels through the power train. The main power train components are: - Torque converter (1) - Drive shaft (2) - Transfer gears (3) - Transmission (4) - Differential (5) - Final drives (6) Other power train components visible in this illustration are the transmission charge filters (7), torque converter charging filter (8), and two-section hydraulic tank (9).

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Text Reference

1

2 3

115 These illustrations show the location of the main electronic components in the power train. The Transmission/Chassis ECM (1) is located behind the cab seat and is accessed by removing a panel at the rear of the cab. The transmission modulating valves (2) are located on top of the transmission planetary gears and are accessed by removing a cover plate. The torque converter lockup clutch solenoid valve (3) is located on the rear of the torque converter. NOTE: The Transmission/Chassis ECM receives input signals from several components located on the machine to control transmission shifting and the torque converter lockup clutch operation. The electronic components will be covered later in the presentation.

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Torque Converter Outlet Relief Valve

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Text Reference

POWER TRAIN HYDRAULIC SYSTEM

To Brake Cooling

To Variable Speed Clutch Control

To To Hoist Pilot Traction Signal Control Resolver Pilot

Transmission Charge Filters

Lockup Valve

Torque Converter

Lockup Clutch Relief Valve

Lockup Clutch Valve Filter Torque Converter Charge Filter

To Brake Cooling

Hydraulic Controls

Transmission Torque Converter Inlet Relief Valve

Transmission Oil Level Switch

116

Shown is the transmission and torque converter hydraulic system for the 777F. A five section pump is located at the rear of the torque converter housing. The first section (attached to pump drive at rear of torque converter) scavenges oil from the bottom of the torque converter case and returns the oil to the hoist, torque converter, and brake hydraulic tank. The second section pumps charge oil through the torque converter filter to the torque converter. The third section sends oil through the lockup clutch filter and provides pilot oil to the following circuits: - Lockup clutch valve - Variable speed fan clutch control - Hoist pilot signal resolver - Traction control valve The fourth section scavenges oil from the transmission sump and sends oil to the transmission oil cooler and the transmission hydraulic tank. The fifth section sends charge oil through the transmission oil filters to the transmission control valves.

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Text Reference

TORQUE CONVERTER HYDRAULIC SYSTEM To Brake Cooling

Torque Converter Charging Filter To Brake Cooling

Inlet Relief Valve Outlet Relief Valve

Lockup Relief Valve

To Variable Speed Fan Clutch Control

To Hoist Pilot Signal Resolver

Lockup Clutch Valve

Lockup Clutch Filter

To TCS Valve Converter Scavenge Screen

117

Torque Converter Hydraulic System This schematic shows the oil flow from the torque converter pump through the torque converter hydraulic system. The scavenge pump section pulls oil through a screen from the torque converter housing and sends the oil to the hoist, torque converter, and brake hydraulic tank. The torque converter charging pump section sends oil through the torque converter charging filter to the torque converter inlet relief valve. Oil flows from the inlet relief valve through the torque converter to the outlet relief valve. Oil flows from the outlet relief valve to the brake oil cooling circuit. The lockup clutch valve pump section sends oil through the lockup clutch valve filter to the torque converter lockup clutch valve. When oil pressure in the lockup clutch valve circuit is too high, the lockup clutch relief valve allows oil to flow to the brake cooling circuit. Oil from the lockup clutch valve pump section also flows to the TCS valve, variable speed clutch control and hoist pilot signal resolver.

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5

Text Reference

3

4

2

1

118

The five sections of the power train pump (from the front to the rear) are: - Torque converter scavenge (1) - Torque converter charging (2) - Lockup clutch valve, hoist pilot circuit, TCS valve, and variable speed fan clutch (3) - Transmission scavenge (4) - Transmission charging (5)

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Turbine

Impeller

Text Reference

TORQUE CONVERTER CONVERTER DRIVE

Stator

Torque Converter Inlet Oil

119

Freewheel Assembly

Torque Converter Lockup Oil Passage

This sectional view shows a torque converter in CONVERTER DRIVE. The lockup clutch (yellow piston and blue discs) is not engaged. During operation, the rotating housing and impeller (red) can rotate faster than the turbine (blue). The stator (green) remains stationary and multiplies the torque transfer between the impeller and the turbine. The output shaft rotates slower than the engine crankshaft, but with increased torque. Lockup Piston

Turbine

Impeller

TORQUE CONVERTER DIRECT DRIVE

Stator

Torque Converter Inlet Oil

120

Freewheel Assembly

Torque Converter Lockup Oil Passage

In DIRECT DRIVE, the lockup clutch is engaged by hydraulic pressure and locks the turbine to the impeller. The housing, impeller, turbine, and output shaft then rotate as a unit at engine rpm. The stator, which is mounted on a one-way clutch, is driven by the force of the oil in the housing. The one-way clutch permits the stator to turn freely in DIRECT DRIVE when torque multiplication is not required.

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Text Reference

2 3 4

121 5

1 6

7

122

The five section power train pump (1) is located at the bottom rear of the torque converter. The inlet relief valve (2) limits the maximum pressure of the supply oil to the torque converter. The torque converter inlet relief pressure can be checked by removing a plug and installing a pressure tap. Normally, the inlet relief pressure will be slightly higher than the outlet relief valve pressure. Oil flows through the inlet relief valve and enters the torque converter. Some of the oil will leak through the torque converter to the bottom of the housing to be scavenged. Most of the oil in the torque converter is used to provide a fluid coupling and flows through the torque converter outlet relief valve (3).

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Text Reference

The outlet relief valve maintains the minimum pressure inside the torque converter. The main function of the outlet relief valve is to keep the torque converter full of oil to prevent cavitation. The outlet relief pressure can be measured at the tap (4) on the outlet relief valve. The torque converter lockup clutch valve (5) directs oil to engage the torque converter lockup clutch. The torque converter lockup clutch pressure can be checked at the tap (6) on top of the lockup clutch valve. Excess oil that accumulates in the bottom of the torque converter is scavenged by the first section of the pump through a screen behind the access cover (7) and returned to the hoist, torque converter, and brake hydraulic tank.

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Text Reference

LOCKUP CLUTCH MODULATING VALVE TORQUE CONVERTER DRIVE Lockup Clutch Pressure Tap

T/C Lockup Solenoid To Lockup Clutch

From Lockup Clutch Pump

123 The torque converter lockup clutch modulating valve contains a proportional solenoid that receives a signal from the Transmission/Chassis ECM to engage and release the torque converter lockup clutch. In this illustration, the lockup clutch modulating valve is shown with no current signal applied to the solenoid (TORQUE CONVERTER DRIVE or NEUTRAL). The Transmission/Chassis ECM controls the rate of oil flow through the lockup clutch modulating valve to the lockup clutch by changing the signal current strength to the solenoid. With no current signal applied to the solenoid, the transmission modulating valve is DE-ENERGIZED and oil flow to the clutch is blocked. Pump oil flows into the valve body around the valve spool and into a drilled passage in the center of the valve spool. The oil flows through the drilled passage and orifice to the left side of the valve spool to a drain orifice. Since there is no force acting on the pin assembly to hold the ball against the drain orifice, the oil flows through the spool and the drain orifice past the ball to the tank. The spring located on the right side of the spool in this view holds the valve spool to the left. The valve spool opens the passage between the clutch passage and the tank passage and blocks the passage between the clutch passage and the pump supply port. Oil flow to the clutch is blocked. Oil from the clutch drains to the tank preventing clutch engagement.

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Text Reference

LOCKUP CLUTCH MODULATING VALVE DIRECT DRIVE

Lockup Clutch Pressure Tap

T/C Lockup Solenoid To Lockup Clutch

From Lockup Clutch Pump

124

In this illustration, the modulating valve is shown with a maximum current signal commanded to the solenoid. When the modulation cycle stops, the Transmission/Chassis ECM sends the maximum specified current signal to fully engage the lockup clutch (DIRECT DRIVE). The constant current signal pushes the pin firmly against the ball in the solenoid valve. The pin force against the ball blocks more oil from flowing through the drain orifice. This restriction causes an increase in pressure on the left side of the valve spool. The valve spool moves to the right to allow pump flow to fully engage the clutch. In a short period of time, maximum pressure is felt at both ends of the proportional solenoid valve spool. This pressure along with the spring force on the right end of the spool cause the valve spool to move to the left until the forces on the right end and the left end of the valve spool are balanced. The valve spool movement to the left (balanced) position reduces the flow of oil to the engaged clutch. The Transmission/Chassis ECM sends a constant maximum specified current signal to the solenoid to maintain the desired clutch pressure. NOTE: The lockup clutch valve is calibrated with Cat ET.

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Text Reference

125

A torque converter outlet temperature sensor (arrow) provides an input signal to the Transmission/Chassis ECM, which sends a signal to the monitoring system to inform the operator of the torque converter outlet temperature.

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Text Reference

126

2

1

Oil from the lockup clutch valve pump section flows to the lockup valve oil filter (1) and then to the lockup clutch modulating valve (2). The filter is located inside of the left frame rail.

3

4

5

127

The filter has a bypass switch (3) which provides an input signal to the monitoring system, via the Transmission/Chassis ECM, to inform the operator if the filter is restricted. The filter housing has an S•O•S tap (4) and a lockup clutch circuit pressure tap (5).

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Text Reference

1

2

128

The lockup clutch relief valve (1) is located inside the left frame rail in front of the lockup clutch filter (2). This view is looking up from the bottom of the truck. When oil pressure in the lockup clutch valve circuit is too high, the lockup clutch relief valve allows oil to flow to the brake cooling circuit.

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Text Reference

129

1

The torque converter charging filter (1) is located on the right frame rail, behind the right front tire. Oil from the torque converter charging pump section flows through the torque converter filter to the torque converter inlet relief valve.

130

2

The torque converter filter includes an S•O•S port (2) located on the bottom of the filter.

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Text Reference

TRANSMISSION HYDRAULIC SYSTEM NEUTRAL

Transmission Oil Temperature Sensor

1

5

Bypass Switch Transmission Cooler

Transmission Charge Pump

Transmission Scavenge Pump

2 6

Screen Screen Transmission Sump

Transmission Hydraulic Tank

Main Relief Valve

Torq Converter Inlet Relief Valve

3

7

4

131

Transmission Hydraulic System The transmission scavenge pump section pulls oil from the bottom of the transmission case through a magnetic screen and sends the oil through the transmission oil cooler to the transmission tank. The magnetic screen should always be checked for debris if a problem with the transmission is suspected. The transmission charging pump section pulls oil from the transmission hydraulic tank. Charging oil flows from the pump through two transmission charging filters to the transmission main relief valve and seven modulating valves. The main relief valve regulates the supply pressure inside the transmission hydraulic system. Oil unseats the check ball and forces the spool to the right if the transmission system pressure becomes greater than the spring force on the right of the spool. Excess oil will flow to the lubrication circuit and the lube relief valve. The lubrication circuit oil and oil from the lube relief valve flows to the transmission sump. The relief valve is adjustable by turning the adjusting screw on the right end of the valve.

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Text Reference

The clutch modulating valves control the engagement of the transmission clutches. The solenoids are controlled by a pulse width modulated (PWM) signal from the Transmission/Chassis ECM. Supply oil flows into the clutch modulating valves and through a passage in the center of the spool. Oil then flows to the tank if the solenoid is not energized. Oil flow is blocked by a ball and seat if the solenoid is energized. The spool will shift down and the clutch will begin to fill. The signal from the Transmission/Chassis ECM determines how long it takes to fill each clutch. The transmission lubrication relief valve limits the transmission lubrication oil pressure.

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Text Reference

132

3

1

133

2

The transmission scavenge pump section (1) pulls oil from the bottom of the transmission case through a magnetic screen and sends the oil through the transmission oil cooler (2) to the transmission tank. The oil cooler is located on the right side of the engine. The transmission charging pump section (3) pulls oil from the bottom of the transmission hydraulic tank through a magnetic screen and sends the oil through the transmission filters to the transmission hydraulic controls.

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Text Reference

4

2

3

1

8 7

5

9

6

134 Oil from the transmission charging pump section is sent to the transmission charge oil filters (1) located on the cross member on the right side of the machine. The rear filter housing has an S•O•S tap (2) and a charge pressure tap (3). The rear filter housing also has a bypass switch (4) which provides an input signal to the monitoring system, via the Transmission/Chassis ECM, to inform the operator if the filter is restricted. The ECPC transmission hydraulic controls can be accessed by removing a cover plate (5) on top of the transmission. The transmission input speed sensor (6) is located on top of the transfer gear housing. The transmission input speed sensor sends an input to the Transmission/Chassis ECM which checks the speed of the drive shaft to the speed of the engine. The transmission has pressure taps located on the outside of the transmission which aids in preventing contamination from entering the transmission as well as saving time when checking the pressures on the 777F transmission. Shown in the lower right illustration are the transmission control valve pressure taps. The transmission lubrication pressure tap (7) and the transmission hydraulic system pressure tap (8) are located toward the rear of the transmission. Oil pressure for the seven clutches can be checked at the remaining seven taps (9) on the transmission.

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4

2

Text Reference

5 6

9

8

3 1

7

135

The transmission modulating valves control the oil to corresponding transmission clutches. The solenoid valves are: - Clutch No. 1 Solenoid valve (1) - Clutch No. 2 Solenoid valve (2) - Clutch No. 3 Solenoid valve (3) - Clutch No. 4 Solenoid valve (4) - Clutch No. 5 Solenoid valve (5) - Clutch No. 6 Solenoid valve (6) - Clutch No. 7 Solenoid valve (7) The main relief valve (8) controls the transmission hydraulic pressure, and the lubrication relief valve (not visible) controls the lubrication pressure. The lubrication relief valve is located below the main relief valve. Also located on the transmission hydraulic control valve is the transmission hydraulic oil temperature sensor (9). The temperature sensor sends a signal to the Transmission/Chassis ECM indicating transmission oil temperature.

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Text Reference

ENGAGEMENT OF TRANSMISSION CLUTCHES Transmission Speed

Engaged Clutches in the Transmission

NEUTRAL

1

REVERSE

1 and 7

FIRST speed

2 and 6

SECOND speed

1 and 6

THIRD speed

3 and 6

FOURTH speed

1 and 5

FIFTH speed

3 and 5

SIXTH speed

1 and 4

SEVENTH speed

3 and 4

136

The table in this illustration lists the solenoids that are energized and clutches that are engaged for each transmission speed. This table can be useful for transmission diagnosis.

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Text Reference

TRANSMISSION MODULATING VALVE NO COMMANDED SIGNAL Test Port Valve Spool

Ball Orifice

Solenoid

Pin

Drain Orifice

To Tank

To Clutch

Spring

From Pump

137

In this illustration, the transmission modulating valve is shown with no current signal applied to the solenoid. The Transmission/Chassis ECM controls the rate of oil flow through the transmission modulating valves to the clutches by changing the signal current strength to the solenoid. With no current signal applied to the solenoid, the transmission modulating valve is DE-ENERGIZED and oil flow to the clutch is blocked. Pump oil flows into the valve body around the valve spool and into a drilled passage in the center of the valve spool. The oil flows through the drilled passage and orifice to the left side of the valve spool to a drain orifice. Since there is no force acting on the pin assembly to hold the ball against the drain orifice, the oil flows through the spool and the drain orifice past the ball to the tank. The spring located on the right side of the spool in this view holds the valve spool to the left. The valve spool opens the passage between the clutch passage and the tank passage and blocks the passage between the clutch passage and the pump supply port. Oil flow to the clutch is blocked. Oil from the clutch drains to the tank preventing clutch engagement.

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Text Reference

TRANSMISSION MODULATING VALVE COMMANDED SIGNAL BELOW MAXIMUM Test Port Ball

Solenoid

Pin

Drain Orifice

Valve Spool

Orifice

To Tank

To Clutch

Spring

From Pump

138

In this illustration, the modulating valve is shown with a signal to the solenoid that is below the maximum current. Clutch engagement begins when the Transmission/Chassis ECM sends an initial current signal to ENERGIZE the solenoid. The amount of commanded current signal is proportional to the desired pressure that is applied to the clutch during each stage of the engagement and disengagement cycle. The start of clutch engagement begins when the current signal to the solenoid creates a magnetic field around the pin. The magnetic force moves the pin against the ball in proportion to the strength of the current signal from the Transmission/Chassis ECM. The position of the ball against the orifice begins to block the drain passage of the oil flow from the left side of the valve spool to the tank. This partial restriction causes the pressure at the left end of the valve spool to increase. The oil pressure moves the valve spool to the right against the spring. As the pressure on the right side of the valve spool overrides the force of the spring, the valve spool shifts to the right. The valve spool movement starts to open a passage on the right end of the valve spool for pump supply oil to fill the clutch. Oil also begins to fill the spring chamber on on the right end of the spool.

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Text Reference

In the initial clutch filling stage, the Transmission/Chassis ECM commands a high current pulse to quickly move the valve spool to start filling the clutch. During this short period of time, the clutch piston moves to remove the clearances between the clutch discs and plates to minimize the amount of time required to fill the clutch. The ECM then reduces the current signal which reduces the pressure setting of the proportional solenoid valve. The change in current signal reduces the flow of oil to the clutch. The point where the clutch plates and discs start to touch is called TOUCH-UP. Once TOUCH-UP is obtained, the Transmission/Chassis ECM begins a controlled increase of the current signal to start the MODULATION cycle. The increase in the current signal causes the ball and pin to further restrict oil through the drain orifice to tank causing a controlled movement of the spool to the right. The spool movement allows the pressure in the clutch to increase. During the MODULATION cycle, the valve spool working with the variable commanded current signal from the Transmission/Chassis ECM acts as a variable pressure reducing valve. The sequence of partial engagement is called desired slippage. The desired slippage is controlled by the application program stored in the Transmission/Chassis ECM.

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Text Reference

TRANSMISSION MODULATING VALVE COMMANDED SIGNAL AT MAXIMUM Test Port Ball

Solenoid

Pin

Drain Orifice

Valve Spool

Orifice

To Tank

To Clutch

Spring

From Pump

139

In this illustration, the modulating valve is shown with a maximum current signal commanded to the solenoid. When the modulation cycle stops, the Transmission/Chassis ECM sends the maximum specified current signal to fully engage the clutch. The constant current signal pushes the pin firmly against the ball in the solenoid valve. The pin force against the ball blocks more oil from flowing through the drain orifice. This restriction causes an increase in pressure on the left side of the valve spool. The valve spool moves to the right to allow pump flow to fully engage the clutch. In a short period of time, maximum pressure is felt at both ends of the proportional solenoid valve spool. This pressure, along with the spring force on the right end of the spool, causes the valve spool to move to the left until the forces on the right end and the left end of the valve spool are balanced. The valve spool movement to the left (balanced) position reduces the flow of oil to the engaged clutch. The Transmission/Chassis ECM sends a constant maximum specified current signal to the solenoid to maintain the desired clutch pressure.

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Text Reference

The different maximum specified pressures for each clutch is caused by different maximum current signals being sent by the Transmission/Chassis ECM to each individual modulating valve. The different maximum signal causes a difference in the force pushing the pin against the ball to block leakage through the drain orifice in each solenoid valve. The different rate of leakage through the spool drain orifice provides different balance positions for the proportional solenoid valve spool. Changing the valve spool position changes the flow of oil to the clutch and the resulting maximum clutch pressure. The operation of the proportional solenoid to control the engaging and releasing of clutches is not a simple on and off cycle. The Transmission/Chassis ECM varies the strength of the current signal through a programmed cycle to control movement of the valve spool. The clutch pressures can be changed using Caterpillar Electronic Technician (ET) during the calibration procedure.

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Text Reference

MAIN RELIEF VALVE Adjusting Screw Ball

Slug

From Pump

140

The transmission hydraulic control relief valve is used to regulate the pressure to the main components in the transmission. Oil enters the relief valve at the supply port. The pressure of the oil unseats the ball and moves the spool toward the right. Oil flows past the spool and to the tank to regulate transmission oil pressure. The adjustment screw alters the preload on the spring to adjust the relief pressure.

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Text Reference

5

7

3 4

2 1

4 1

6 5

2

141 Rear Axle Check the differential oil level by removing the magnetic inspection plug (1). The oil should be level with the bottom of the fill plug opening. The magnetic inspection plug should be removed at regular intervals and checked for metal particles. The plug (2) at the bottom of the differential housing is used to drain the oil. The optional remote grease fittings (3) are located on top of the differential. Inspect the condition of the rear axle breather (4) at regular intervals. The breather prevents pressure from building up in the axle housing. Excessive pressure in the axle housing can cause brake cooling oil to leak through the Duo-Cone seals in the wheel brake assemblies. The parking brake oil pressure can be checked at the pressure taps (5) on top of the axle. A differential carrier thrust pin is located behind the small cover (6). The thrust pin prevents movement of the differential carrier during high thrust load conditions. The backup alarm (7) is located on top of the rear frame. When the machine is in reverse, the Transmission/Chassis ECM sends a signal to sound the back-up alarm.

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Text Reference

142

Shown is the differential removed from the rear axle housing. The differential is located in the rear axle housing behind the transmission. Power flows from the transmission to the differential. The differential divides the power to the right and left axle shafts. Torque is transmitted equally from the differential through the two axle shafts to the final drives. The differential adjusts the speed of the axle shafts for vehicle cornering, therefore, the power delivered to the axle shafts is unequal during cornering. The differential thrust pin contacts the differential carrier at the location shown (arrow). When high thrust loads are transmitted from the differential pinion to the differential ring gear, the carrier tries to move away from the pinion. The thrust pin prevents movement of the differential carrier during high thrust load conditions.

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Text Reference

TRANSMISSION / CHASSIS CONTROL MODULE SYSTEM DIAGRAM Cat Data Link OUTPUTS

INPUTS Key Start Switch Machine Lockout Switch

Torque Converter Oil Temperature Sensor

Starter Lockout Switch

Transmission Oil Temperature Sensor

QuickEvac Service Tool Input

Primary Steering Pressure Switch

Secondary Steer Test Switch

Secondary Steering Motor State

Drive Gear Select Switches

Transmission Input Speed Sensor

Shift Lever Position Sensor

Alternator R-Terminal Hoist Lever Position Sensor Fuel Level Sender Engine Speed Sensor Head Lamp Sense Inclinometer

Transmission Charge Filter Bypass Switch Transmission Output Speed Sensor 1 Transmission Output Speed Sensor 2 Transmission Oil Level Switch Location Codes

Body Up Switch Autolube Pressure Sensor

Secondary Steering Pressure Switch Secondary Brake Pressure Switch Service Brake Pressure Switch Lockup Clutch Filter Bypass Switch

Start Relay Transmission Solenoids 1-7

Steering System Disable Solenoid Service Brake Accumulator Bleed Solenoid Lockup Clutch Solenoid Hoist Raise Solenoid Hoist Lower Solenoid Secondary Steering / QuickEvac / Prelube Relay Back-up Alarm Autolube Relay Stop Lamp Relay Backup Lamp Relay Secondary Steering Relay Starter Lockout Lamp Machine Lockout Lamp Backlight Intensity

143

Transmission/Chassis Electronic Control System Shown in this illustration are the transmission/chassis electronic control system inputs and outputs for the 777F trucks. The main purpose of the Transmission/Chassis ECM is to determine the desired transmission gear and energize the appropriate solenoids to shift the transmission up or down as required based on information from both the operator and machine. The Transmission/Chassis ECM also controls all the hoist functions, the steering disable function, and other functions as described in this presentation. The Transmission/Chassis ECM receives information from various input components such as the shift lever switch and the transmission output speed sensors. Based on the input information, the Transmission/Chassis ECM determines whether the transmission should upshift, downshift, engage the lockup clutch, or limit the transmission gear. These actions are accomplished by sending signals to various output components.

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Text Reference

Power train output components include the transmission modulating valve solenoids and lockup clutch solenoid. Several other Transmission/Chassis ECM output components are covered throughout the presentation. The Engine ECM, the monitoring system, the Transmission/Chassis ECM, and the Brake ECM all communicate with each other through the CAT Data Link. Communication between the electronic control modules allows the sensors of each system to be shared. Many additional benefits are provided, such as Controlled Throttle Shifting (CTS). CTS occurs when the Transmission/Chassis ECM tells the Engine ECM to reduce or increase engine fuel during a shift to lower stress to the power train. The Electronic Technician (ET) Service Tool can be used to perform several diagnostic and programming functions. NOTE: Some of the Transmission/Chassis ECM input and output components are shown during the discussion of other systems.

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Text Reference

144

The Transmission/Chassis ECM (arrow) is located in the compartment at the rear of the cab. The Transmission/Chassis ECM performs the transmission control functions, plus some other machine functions (hoist and secondary steering control). Because of the functionality of the control, it is referred to as the Transmission/Chassis ECM. The Transmission/Chassis ECM is an A4M1 module with two 70-pin connectors. The Transmission/Chassis ECM communicates with the Engine ECM, Brake ECM, and monitoring system over the CAT Data Link and can communicate with some attachments over the CAN Datalink.

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Text Reference

1

6 2

8

7

4

5 3

145 At the base of the shift lever (1) is a position sensor (2) which provides input signals to the Transmission/Chassis ECM when the operator moves the lever. The shift lever position sensor is a Hall effect position sensor. The shift lever is connected to a device which contains two magnets. One magnet (3) is visible in the bottom left view. As the lever is moved, the magnets pass over the Hall Cell (4) and the change in the magnetic field produces a signal. The internal electronics (5) of the sensor process the signal and send a PWM signal to the ECM. The lever position sensor receives 24 VDC from the machine electrical system. The sensor contains a fourth pin that is used for calibration on some machine applications. The following measurements would be typical for the position sensor with the sensor connected to the Transmission/Chassis ECM and the key switch turned ON: • Pin 1 to Pin 2 -- Supply Voltage • Pin 3 to Pin 2 -- .7 - 6.9 DCV on DC volts scale • Pin 3 to Pin 2 -- 4.5 - 5.5 KHz on the KHz scale • Pin 3 to Pin 2 -- 5% - 95% duty cycle on the % scale

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Text Reference

Also shown in the top right illustration is the drive gear UP switch (6) and the drive gear DOWN switch (7). The drive gear switches are toggle switches that send a signal to the Transmission/Chassis ECM. When the drive gear UP switch is pressed, the high gear limit can be increased up to seventh gear. When the drive gear DOWN switch is pressed, the high gear limit can be decreased down to third gear. The transmission shift lever lock button (8) unlocks the transmission shift lever when pressed.

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Text Reference

146

The transmission output speed sensors are located on the transfer gear housing on the input end of the transmission behind a cover (arrow). Although the sensors are physically located near the input end of the transmission, the sensors are measuring the speed of the transmission output shaft. The sensors are two wire passive sensors. The passive speed sensor uses the passing teeth of the output shaft to provide a frequency signal. The signal from the sensor is used for automatic shifting of the transmission. The signal is also used to drive the speedometer and as an input to other electronic controls. The Transmission/Chassis ECM also performs a check between the two measured transmission output speeds and the transmission input speed to ensure that the ECM calculates an accurate transmission speed. This check also uses the speeds to determine the direction of motion of the machine.

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Text Reference

147

The engine speed sensor (arrow) is located at the rear of the engine on the left side of the gear housing. The engine speed sensor sends a frequency signal to the Transmission/Chassis ECM indicating engine speed. The Transmission/Chassis ECM uses the engine speed signal input to determine actual engine speed. The actual engine speed is one of the parameters used to determine the proper transmission shift points.

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Text Reference

148

The transmission oil level switch (arrow), located near the bottom of the transmission tank, sends a signal to the Transmission/Chassis ECM indicating the hydraulic oil level in the transmission tank.

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Text Reference

1 2

149 The body up switch (1) is located on the frame near the body pivot pin. This magnetic switch is normally open. When the body is raised, a magnet (2) mounted on the body passes the switch and causes the switch to close. The resulting ground signal is sent to the Transmission/Chassis ECM. This signal is used to limit the top gear into which the transmission will shift when the body is up. The body up top gear value is programmable from FIRST to THIRD utilizing the Cat ET Service Tool. The ECM comes from the factory with this value set to FIRST gear. When driving away from a dump site, the transmission will not shift past FIRST gear until the body is down. If the transmission is already above the set limit gear when the body is raised, no limiting action will take place. The body up switch signal is also used to control the SNUB position of the hoist control valve. As the body is lowered and the magnet passes the body up switch, the Transmission/Chassis ECM signals the hoist lower solenoid to move the hoist valve spool to the SNUB position. In the SNUB position, the body float speed is reduced to prevent the body from making hard contact with the frame. The body up switch input provides the following functions: - Body up gear limiting - Illuminates the backup lights - Hoist snubbing - Lights the body up dash lamp - Signals a new load count (after 10 seconds in the RAISE position)

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Text Reference

A diagnostic code occurs if the Transmission/Chassis ECM does not receive a closed (ground) signal from the switch within four hours of operation time or an open signal from the switch within one hour of operation time. The body up switch must be adjusted properly for all of the functions to operate correctly. The body position switch can be raised or lowered slightly in the bracket notches to start the SNUB feature sooner or later. NOTE: The snub feature can also be adjusted in the Cat ET hoist configuration screen by selecting the "Hoist lower valve adjustment status."

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Text Reference

TRANSMISSION / CHASSIS ECM SYSTEMS CONTROLLED BY ECM - Transmission Shifting

- Torque Converter Lockup

- Top Gear Limit

- Machine Overload Speed Limit

- Anti-hunt

- Machine Speed Limit

- Reverse Inhibitor

- Body Hoist

- Machine Lockout

- Engine Oil Pre-lubrication

- Engine Lockout

- Sound Reduction

- Neutral Start

- Back-up Alarm

- Shift Counter

- Control Throttle Shifting (CTS)

- Throttle Lock

- Directional Shift Management

- Secondary Steering

- Neutral Coast Inhibiting

150

Besides controlling the Transmission Shifting and Torque Converter Lockup, the Transmission/Chassis ECM also controls other functions as shown above, such as Control Throttle Shifting (CTS), Directional Shift Management, and Top Gear Limit. There are several programmable parameters available with the Transmission/Chassis ECM. NOTE: Refer to the Transmission/Chassis Electronic Control System Operation, Troubleshooting, Testing, and Adjusting manual (RENR8342) for more information on the additional Transmission/Chassis ECM functions and programmable parameters.

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Text Reference

4 3

2

1

5

151

STEERING SYSTEM The steering system on the 777F is similar to the 777D except a steering disable solenoid valve has been added and some of the component locations have changed. When energized, the steering disable solenoid valve stops the oil flow coming from the steering pump. This prevents the front wheels from turning to allow servicing to be conducted safely in the front wheel area. The steering system uses a load sensing, pressure compensated pump. Minimal horsepower is used by the steering system when the truck is traveling in a straight path. Steering hydraulic horsepower requirements depend on the amount of steering pressure and flow required by the steering cylinders. This illustration shows the following main steering components: - Steering pump (1)

- HMU (3)

- Steering disable valve and steering valve (2)

- Steering tank (4) - Secondary steering pump (5)

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Text Reference

152

1

3

4

2

153

3

The steering system tank is located on the right platform Check the steering system oil level at the sight gauge (1). The steering system oil filter (2) is located on the side of the steering tank. The steering system uses a pressure compensated piston type pump. Case drain oil from the steering pump returns to the hydraulic tank through a case drain filter (3) on the side of the steering tank. Before removing the cap to add oil to the steering system, depress the pressure release button (4) on the breather to release any remaining pressure from the tank.

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Text Reference

The steering system filter base and the case drain filter base have bypass valves that allow the steering oil to bypass the filters if they are plugged.

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Text Reference

2 1

154

The 777F Trucks are equipped with a load sensing, pressure compensated, piston-type pump. The steering pump operates only when the engine is running and provides the necessary flow of oil for steering system operation. The steering pump contains a load sensing controller with two valves. The high pressure cutoff valve (1) functions as the primary steering system relief valve. The flow compensator valve (2) is used to adjust the low pressure standby setting. When the truck is traveling in a straight path, virtually no flow or pressure is sent to the steering cylinders, and the pump destrokes to low pressure standby.

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Load Sensing Pressure from HMU

Text Reference

STEERING PUMP

To Steering Valve and HMU

LOW PRESSURE STANDBY

High Pressure Cutoff Valve

Actuator Piston

Flow Compensator Load Sensing Controller

Case Drain Filter

Swashplate Piston

155

When the truck is traveling in a straight path, the steering cylinders require virtually no flow or pressure. The HMU provides a very low pressure load sensing signal to the flow compensator in the load sensing controller. Pump oil (at low pressure standby) flows to the swashplate piston and past the lower end of the displaced flow compensator spool to the actuator piston. The actuator piston has a larger surface area than the swashplate piston. The oil pressure at the actuator piston overcomes the spring force and the oil pressure in the swashplate piston and moves the swashplate to destroke the pump. The pump is then at minimum flow, low pressure standby. Pump output pressure is equal to the setting of the flow compensator plus the pressure required to compensate for system leakage.

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Load Sensing Pressure from HMU

To Steering Valve and HMU

High Pressure Cutoff Valve

Text Reference

STEERING PUMP MAXIMUM FLOW

Actuator Piston

Flow Compensator Load Sensing Controller Swashplate Piston Case Drain Filter

156

During a turn, when steering pressure and flow are required, pressure increases in the HMU load sensing signal line. The pressure in the signal line is equal to the pressure in the steering cylinders. The pump load sensing controller is spring biased to vent the actuator piston pressure to drain. Venting pressure from the load sensing controller and the actuator piston positions the spring biased swashplate to maximum displacement (maximum flow). As pressure increases in the HMU load sensing signal line, pump supply pressure is sensed on both ends of the flow compensator. When pressure is present on both ends of the flow compensator, the swashplate is kept at maximum angle by the force of the spring in the pump housing and pump discharge pressure on the swashplate piston. The pistons reciprocate in and out of the barrel and maximum flow is provided through the outlet port. Since the pump is driven by the engine, engine rpm also affects pump output.

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Text Reference

2 3

1

4

157

The steering disable valve (1) is located behind the shock on the right frame rail. When the steering disable solenoid valve (2) is energized, oil flow from the steering pump to the steering valve is blocked by the steering disable valve, which allows servicing behind the front wheels with the machine running. When the machine lockout switch, located under a panel on the left stairway, is toggled, a signal is sent to the Transmission/Chassis ECM. The Transmission/Chassis ECM energizes the steering disable solenoid allowing service to be performed behind the front wheels safely. Also located on the steering disable valve is a pressure tap (3) for checking the load sensing signal to the pump, and an S•O•S tap (4).

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1

Text Reference

2

158

Steering oil flows from the pump through the steering disable valve to the steering valve (1) located on the frame behind the right front suspension cylinder. The primary steering pressure switch (2) monitors the output of the steering pump. The steering pressure switch provides input signals to the Transmission/Chassis ECM which sends a signal to the monitoring system to inform the operator of the steering system condition. A steering system warning is displayed if the pressure is too low. The steering pressure switch cannot tolerate high steering system pressures. A pressure reducing valve (not visible) reduces the steering system pressure to the steering pressure switch. Two relief valves are located on the front of the steering valve. The secondary steering back-up relief valve protects the secondary steering system if the relief valve on the secondary steering pump malfunctions. The primary steering back-up relief valve protects the primary steering system if the high pressure cutoff valve on the steering pump malfunctions. Primary steering pressure is first controlled by the high pressure cutoff valve located on the steering pump. Steering system pressures can be measured at the steering system pressure tap located on the front of the steering valve.

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Text Reference

159

This illustration shows the location of the HMU (arrow) for the 777F. Serviceability has improved for the HMU on the 777F due to the redesigned walkways. The HMU is connected to the steering wheel and controlled by the operator. The HMU meters the amount of oil sent to the steering cylinders by the speed at which the steering wheel is turned. The faster the HMU is turned, the higher the flow sent to the steering cylinders, and the faster the wheels will change direction. The steering system is referred to as "Q-amp" which means flow amplification. During a sudden steering change (steering wheel speed greater than 10 rpm), additional steering pump oil flow will bypass the gerotor pump in the HMU and flow directly to the steering cylinders. Steering oil flow to the cylinders is equal to the gerotor pump oil flow plus the bypass oil flow from the steering pump. The steering oil flow is amplified up to 1.6 to 1. The purpose of the flow amplification is to provide quick steering response when sudden steering changes are needed. Two crossover relief valves are installed in the top of the HMU. The crossover relief valves are installed in series with the left and right turn ports. If an outside force is applied to the front wheels while the steering wheel is stationary, the crossover relief valves provide circuit protection for the steering lines between the steering cylinders and the HMU. The crossover relief valves allow oil to transfer from one end of the steering cylinders to the opposite end of the cylinders.

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Text Reference

To test the right crossover relief valve, install two tees with pressure taps in the right turn steering hose at the steering cylinders. Steer the truck completely to the right against the stops, and shut off the engine. An external pump supply must be connected to one of the pressure taps on the right turn hose. Connect a pressure gauge to the other pressure tap on the right turn hose. Pressurize the steering system, and the reading on the gauge will be the setting of the right crossover relief valve. To test the left crossover relief valve, install two tees with pressure taps in the left turn steering hose at the steering cylinders. Steer the truck completely to the left against the stops, and shut off the engine. An external pump supply must be connected to one of the pressure taps on the left turn hose. Connect a pressure gauge to the other pressure tap on the left turn hose. Pressurize the steering system, and the reading on the gauge will be the setting of the left crossover relief valve.

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Text Reference

160 2

3

1

4

5 4

2

3

1

161 6

The electric secondary steering pump (1) and motor (2) on the 777F are the same as the 777D, however the location has changed. The pump and motor are now located on the front of the front frame crossmember. The pump and motor assembly also includes the brake release pump section (3) and the pre-lubrication (QuickEvac) pump section (4). The secondary pressure switch (5) is also mounted next to the secondary steering pump. The pressure switch detects if the wheels are being turned via the steering wheel when secondary steering is activated. When the wheel is turned in a secondary steering condition, the pressure switch will signal the Transmission/Chassis ECM.

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Text Reference

If the primary steering pressure switch signals the Transmission/Chassis ECM that the steering system pressure is low, the ECM will energize the secondary steering relay located behind the cab. The secondary steering relay will then energize a second larger relay located on the left frame, which will then energize the secondary steering motor. The primary relief valve for the secondary steering is accessible through the small allen head plug (6). To check the setting of the secondary steering primary relief valve, do not start the truck. Turn ON the key start switch and depress the secondary steering switch in the cab. Turn the steering wheel hard to the left or right while the secondary steering pump is running. Secondary steering system pressures can be measured at the steering system pressure tap.

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STEERING HYDRAULIC SYSTEM

Text Reference

Crossover Relief Valves

LOW PRESSURE STANDBY

HMU Secondary Steering Back-up Relief Valve

Load Sensing Valve

Primary Steering Back-up Relief Valve Steering Valve

Transmission Chassis ECM

Secondary Pressure Switch

Pressure Reducing Valve

Primary Steering Pressure Switch

Piston Pump and Load Sensing Controller

M

Secondary Steering Primary Relief Valve

Secondary Steering Pump

Flow Compensator Steering Disable Valve

Actuator Piston Swashplate Piston

Steering Filter Case Drain Filter

162

Shown is a schematic of the steering hydraulic system in the HOLD position. The primary steering pump pulls oil from the steering tank. All piston-type pumps produce a small amount of leakage to the case drain circuit for lubrication and cooling. The case drain oil flows to the steering tank through a case drain filter. Steering oil flows from the pump to the steering disable valve. When the steering disable valve is de-energized, oil is allowed to flow to the steering valve. In the steering valve, a steering pressure switch monitors the output of the steering pump. The steering pressure switch cannot tolerate high steering system pressures. A pressure reducing valve lowers the steering system pressure to the steering pressure switch. If the steering pressure switch signals the Transmission/Chassis ECM that the steering system pressure is low, the ECM will then energize the secondary steering motor. Secondary steering supply oil will flow to the steering valve.

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Text Reference

Two relief valves are installed in the steering valve. The secondary steering back-up relief valve protects the secondary steering system if the relief valve on the secondary steering pump malfunctions. The primary steering back-up relief valve protects the primary steering system if the high pressure cutoff valve on the steering pump malfunctions. Two check valves are located on the steering valve. The check valves are used to separate the primary and secondary steering systems. Steering supply oil flows to the HMU from the steering valve. Return oil from the HMU flows through the steering valve and the steering filter to the steering tank. The HMU meters the amount of oil sent to the steering cylinders by the speed at which the steering wheel is turned. The faster the HMU is turned, the higher the flow sent to the steering cylinders, and the faster the wheels will change direction. Two crossover relief valves are installed in the top of the HMU. The crossover relief valves are installed in series with the left and right turn ports. If an outside force is applied to the front wheels while the steering wheel is stationary, the crossover relief valves provide circuit protection for the steering lines between the steering cylinders and the HMU. The crossover relief valves allow oil to transfer from one end of the steering cylinders to the opposite end of the cylinders. When the Transmission/Chassis ECM energizes the secondary steering motor, load sensing signal oil will flow from the secondary steering load sensing valve through the load sensing resolver to the HMU. The load sensing valve uses the load sensing signal pressure to control the amount of flow from the secondary steering pump to the steering valve. The 777F Trucks use a dynamic load sensing steering system the same as the late model "D Series" Trucks. In a dynamic system, there is load sensing pressure and flow between the HMU and the steering pumps. A load sensing pilot signal resolver valve is located in the steering disable valve. The resolver valve allows load sensing signal oil to flow between the HMU and the primary steering pump or the secondary steering pump. In the NO STEER position, oil flows to the HMU. In a LEFT or RIGHT STEER position, oil also flows from the HMU to the resolver valve. Normally, the secondary steering pump is OFF and the resolver is closed from the HMU to the secondary steering pump. The flow from the primary steering pump holds the resolver open and load sensing pilot signal pressure is present between the HMU and the piston pump flow compensator. The load sensing signal flow from the primary steering pump is also used for "thermal bleed" through the HMU. The "thermal bleed" is used to keep the HMU temperature the same as the rest of the steering system. Keeping the HMU the same temperature prevents sticking.

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Text Reference

4 3 1

3

2

163

HOIST SYSTEM The hoist system on the 777F Update trucks is electronically controlled by the Transmission/Chassis ECM. The hoist control system operates similar to the 777D trucks. The main components in the hoist system are: - Hoist control lever and position sensor (in cab) - Hoist pump (1) - Hoist control valve (2) - Hoist cylinders (3) - Hydraulic oil tank (4)

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Text Reference

164

The operator controls the hoist lever (arrow). The four positions of the hoist lever are RAISE, HOLD, FLOAT, and LOWER. The hoist valve has a fifth position referred to as the SNUB position. The operator is unaware of the SNUB position because a corresponding lever position is not provided. When the body is being lowered, just before the body contacts the frame, the Transmission/Chassis ECM signals the hoist lower solenoid to move the hoist valve spool to the SNUB position. In the SNUB position, the body float speed is reduced to prevent the body from making hard contact with the frame. The hoist system can be enabled or disabled using ET. All trucks shipped from the factory without bodies installed are set at the DISABLED mode. The DISABLED mode is a test mode only and will prevent the hoist cylinders from accidentally being activated. After the body is installed, change the hoist system to the ENABLED mode for the hoist system to function properly. The truck should normally be operated with the hoist lever in the FLOAT position. Traveling with the hoist in the FLOAT position will make sure the weight of the body is on the frame and body pads and not on the hoist cylinders. The hoist control valve will actually be in the SNUB position. If the transmission is in REVERSE when the body is being raised, the hoist lever sensor is used to shift the transmission to NEUTRAL. The transmission will remain in NEUTRAL until the hoist lever is moved into the HOLD or FLOAT position and the shift lever has been cycled into and out of NEUTRAL. NOTE: If the truck is started with the body raised and the hoist lever in FLOAT, the lever must be moved into HOLD and then FLOAT before the body will lower.

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Text Reference

1

3

2

165

The hoist lever (1) controls a position sensor (2). The PWM sensor sends duty cycle input signals to the Transmission/Chassis ECM. The hoist lever position sensor is a Hall effect position sensor and operates the same as the transmission shift lever sensor (3) previously described. Depending on the position of the sensor and the corresponding duty cycle, one of the two solenoids located on the hoist valve is energized. The four positions of the hoist lever are RAISE, HOLD, FLOAT, and LOWER, but since the sensor provides a duty cycle signal that changes for all positions of the hoist lever, the operator can modulate the speed of the hoist cylinders. The hoist lever sensor performs three functions: - Raises and lowers the body - Neutralizes the transmission in REVERSE - Starts a new TPMS cycle

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Text Reference

3

1 2

166

Shown is the hoist, converter, and brake hydraulic tank. The oil level is checked by opening the small door (1) and looking at the sight gauge. The oil level should first be checked with cold oil and the engine stopped. The level should again be checked with warm oil and the engine running. The lower sight gauge (2) can be used to fill the tank when the hoist cylinders are in the RAISED position. When the hoist cylinders are lowered, the hydraulic oil level will increase. After the hoist cylinders are lowered, check the hydraulic tank oil level with the upper sight gauge as explained above. Check the hoist, converter, and brake hydraulic tank breather (3) for restriction. Clean the filter if it is restricted.

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Text Reference

3

2 4 5 1

6

7

8

167

Shown is the rear of the hoist, converter, and brake hydraulic tank. The hoist pump pulls oil from the tank through the suction screen (1) located in the rear of the tank. Oil returns from the hoist valve through the port (2). Brake cooling oil returns to the hydraulic tank through the three upper ports (3). Other ports located on the hydraulic tank are: - Transmission charging pump suction (4) - Transmission return (5) - Torque converter pump suction (6) - Brake cooling pump suction (7) - Torque converter inlet relief valve return (8)

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Text Reference

168 1

1

169 2

The hoist pump (1) is a gear type pump that is attached to the drive gear at the rear of the engine. Mounted to the hoist pump is the brake cooling pump and the brake charging pump. Oil flows from the hoist pump to the hoist control valve. The hoist system relief pressures are different in the RAISE and LOWER positions. The body up switch must be in the RAISE position before the LOWER relief valve setting can be tested. Move a magnet past the body up switch until the body up alert indicator on the dash turns ON. If the body up switch is in the LOWER position, the Transmission/Chassis ECM will hold the hoist valve in the SNUB position and the LOWER relief valve will not open.

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Text Reference

In the HOLD, FLOAT and SNUB positions, the gauge will show the brake cooling system pressure, which is a result of the restriction in the coolers, brakes and hoses (normally much lower than the actual oil cooler relief valve setting). The maximum pressure is limited by the oil cooler relief valve. Hoist pump pressure can be checked at the pressure tap (2) on the pump.

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Text Reference

2 2

1

170

The hoist control valve (1) is located behind the engine on the right side of the frame. The hoist valve is the same as the hoist control valve on the 777D. The hoist valve uses torque converter lockup clutch pump oil as the pilot oil to shift the directional spool inside the hoist valve. Lockup clutch pump oil enters the hydraulic actuators (2) on both ends of the hoist valve.

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Text Reference

7 6 1

2

3

4

5

171

Pilot oil pressure is always present at both ends of the directional spool. Two solenoid valves are used to drain the pilot oil from the ends of the directional spool, which then allows the spool to move. The solenoid on the right is the RAISE solenoid valve (1), and the solenoid on the left is the LOWER solenoid valve (2). The left pressure tap (3) is used to check the pilot pressure of the hoist lower solenoid. The right pressure tap (4) is used to check the pilot pressure of the raise solenoid. When the Transmission/Chassis ECM receives an input signal from the hoist lever sensor, the ECM sends an output signal current between 0 and 1.9 amps to one of the solenoids. The amount of current sent to the solenoid determines how much pilot oil is drained from the end of the directional spool and, therefore, how far the directional spool travels toward the solenoid. An oil cooler relief valve is located in the hoist control valve behind the large plug (5). The relief valve limits the brake oil cooling pressure when the hoist valve is in the HOLD, FLOAT, or SNUB position. The hoist system relief pressures are controlled by the two relief valves located on top of the hoist valve. The RAISE relief valve (6) limits the pressure in the hoist system during RAISE. The LOWER relief valve (7) limits the pressure in the hoist system during LOWER. NOTE: The hoist valve LOWER position (snub adjustment) is an adjustable parameter in the Transmission/Chassis ECM using Cat ET. The slight adjustment provides a means to compensate for valve differences. This is the snub adjustment.

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Text Reference

2 3

1

172

The hoist cylinder lower circuit pressure tap (1) and raise circuit pressure tap (2) are located on the bottom of the hoist control valve (3). The relief valve pressure setting is tested with the engine at HIGH IDLE and the hoist valve in the RAISE or LOWER position. The body up switch at the frame near the body pivot pin must be in the RAISE position before the LOWER relief valve setting can be tested. Move a magnet past the body up switch until the body up alert indicator on the dash turns ON. If the body up switch is in the LOWER position, the Transmission/Chassis ECM will hold the hoist valve in the SNUB position and the LOWER relief valve will not open. An orifice plate is installed between the upper hose and the rod end port on both hoist cylinders. The orifice plate restricts the flow of oil from the rod end of the hoist cylinders. The orifice plate also prevents cavitation of the cylinders when the body raises faster than the pump can supply oil to the cylinders (caused by a sudden shift of the load). NOTE: If the snub feature is not adjusted correctly, residual pressure will exist in the head side of the cylinders and the body will not rest on the frame. The raise circuit pressure tap should be used to ensure there is no residual pressure in the head side of the cylinders. Otherwise, when checking the raise (high) circuit pressure, the pressure tap on the hoist pump is easier to access.

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Text Reference

Raise Solenoid

Low Pressure Relief Valve

Brake Cooling Relief Valve

Torque Converter Lockup Clutch Pressure

Main Relief Dump Valve

To Brake Cooling

High Pressure Relief Valve

To Hoist Cylinder Rod End

Dual Stage Relief Valve Signal Stem Load Check Valve

To Hoist Cylinder Head End

HOIST CONTROL VALVE HOLD

Torque Converter Lockup Clutch Pressure Lower Solenoid

173

This illustration shows a sectional view of the hoist control valve in the HOLD position. Pilot oil pressure is present at both ends of the directional spool. The spool is held in the centered position by the centering springs and the pilot oil. Passages in the directional spool vent the dual stage relief valve signal stem to the tank. All the hoist pump oil flows through the brake oil coolers to the rear brakes. The position of the directional spool blocks the oil in the head end and rod end of the hoist cylinders. A gauge connected to a pressure tap at the pump while the hoist valve is in the HOLD position will show the brake cooling system pressure, which is a result of the restriction in the coolers, brakes and hoses. The maximum pressure in the circuit should correspond to the setting of the brake oil cooler relief valve.

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Text Reference

ON Raise Solenoid

Low Pressure Relief Valve

Brake Cooling Relief Valve

Torque Converter Lockup Clutch Pressure

Main Relief Dump Valve

To Brake Cooling

High Pressure Relief Valve

From Hoist Cylinder Rod End

Dual Stage Relief Valve Signal Stem

To Hoist Cylinder Head End

Load Check Valve

HOIST CONTROL VALVE RAISE

Torque Converter Lockup Clutch Pressure Lower Solenoid

174

In the RAISE position, the raise solenoid is ENERGIZED and drains pilot oil from the upper end of the directional spool. The directional spool moves up. Pump oil flows past the load check valve and the directional spool to the head end of the hoist cylinders. When the directional spool is initially shifted, the load check valve remains closed until the supply pressure is higher than the pressure in the hoist cylinders. The load check valve prevents the body from dropping before the RAISE pressure increases. The directional spool also sends hoist cylinder raise pressure to the dual stage relief valve signal stem. The dual stage relief valve signal stem moves down and blocks the supply pressure from opening the low pressure relief valve. Oil flowing from the rod end of the hoist cylinders flows freely through the brake oil cooler to the brakes. If the pressure in the head end of the hoist cylinders exceeds the relief valve settings, the high pressure relief valve will open. When the high pressure relief valve opens, the dump valve moves to the left and pump oil flows to the tank.

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Text Reference

The high pressure hoist relief valve setting is checked at the hoist pump pressure tap or the head end pressure tap. Check the relief pressure with the hoist lever in the RAISE position and the engine at HIGH IDLE.

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Text Reference

Raise Solenoid

Low Pressure Relief Valve

Brake Cooling Relief Valve

Torque Converter Lockup Clutch Pressure

Main Relief Dump Valve

To Brake Cooling

High Pressure Relief Valve

To Hoist Cylinder Rod End

Dual Stage Relief Valve Signal Stem

From Hoist Cylinder Head End

Load Check Valve

HOIST CONTROL VALVE LOWER/POWER DOWN

Torque Converter Lockup Clutch Pressure

ON

Lower Solenoid

175

In the LOWER (power down) position, the LOWER solenoid is energized and drains pilot oil from the lower end of the directional spool. The directional spool moves down. Supply oil from the pump flows past the load check valve and the directional spool to the rod end of the hoist cylinders. Oil in the head end of the hoist cylinders flows to the tank through holes in the directional spool. The supply oil in the rod end of the cylinders and the weight of the body move the cylinders to their retracted positions. Just before the body contacts the frame, the body up switch sends a signal to the Transmission/Chassis ECM to move the directional spool to the SNUB position. In the SNUB position, the directional spool moves slightly to restrict the flow of head end oil through only some of the holes in the spool which allows the body to lower gradually. The directional spool also vents the passage to the dual stage relief valve signal stem. The dual stage relief valve signal stem allows supply pressure to be limited by the low pressure relief valve. If the pressure in the rod end of the hoist cylinders is too high, the low pressure relief valve will open. When the low pressure relief valve opens, the dump valve moves to the left and pump oil flows to the tank.

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Text Reference

The low pressure hoist relief valve setting is checked at the rod end pressure tap. Check the relief pressures with the hoist lever in the LOWER position and the engine at HIGH IDLE. The body up switch must be in the RAISE position before the LOWER relief valve setting can be tested. Move a magnet past the body up switch until the body up alert indicator on the dash turns ON. If the body up switch is in the LOWER position, the Transmission/Chassis ECM will hold the hoist valve in the SNUB position and the LOWER relief valve will not open.

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Text Reference

Raise Solenoid Low Pressure Relief Valve

Brake Cooling Relief Valve

Torque Converter Lockup Clutch Pressure

Main Relief Dump Valve

To Brake Cooling

High Pressure Relief Valve

To Hoist Cylinder Rod End

Dual Stage Relief Valve Signal Stem

From Hoist Cylinder Head End

Load Check Valve

HOIST CONTROL VALVE FLOAT

Torque Converter Lockup Clutch Pressure

ON

Lower Solenoid

176

In the FLOAT position, the LOWER solenoid is partially energized and drains some of the pilot oil at the lower end of the directional spool to the tank. The directional spool moves down. Because the pilot oil is only partially drained, the directional spool does not move down as far as during LOWER (power down). Pump supply oil flows past the load check valve and the directional spool to the rod end of the hoist cylinders. Oil in the head end of the hoist cylinders flows to the tank. The position of the directional spool permits the pressure of the oil flowing to the brake oil cooler to be felt at the rod end of the hoist cylinders. The truck should normally be operated with the hoist lever in the FLOAT position. Traveling with the hoist in the FLOAT position will make sure the weight of the body is on the frame and body pads and not on the hoist cylinders. The hoist valve will actually be in the SNUB position.

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Text Reference

Raise Solenoid

Low Pressure Relief Valve

Brake Cooling Relief Valve

Torque Converter Lockup Clutch Pressure

Main Relief Dump Valve

To Brake Cooling

High Pressure Relief Valve

To Hoist Cylinder Rod End

Dual Stage Relief Valve Signal Stem

From Hoist Cylinder Head End

Load Check Valve

HOIST CONTROL VALVE SNUB

Torque Converter Lockup Clutch Pressure

ON

Lower Solenoid

177

In the SNUB position as the body is lowered, just before the body contacts the frame, the body up switch sends a signal to the Transmission/Chassis ECM to move the directional spool to the SNUB position. In the SNUB position, the directional spool moves slightly to a position between HOLD and FLOAT. The SNUB position restricts the flow of oil and lowers the body gradually. The operator does not control the SNUB position. When the hoist lever is in the LOWER or FLOAT position and the body up switch is in the DOWN position, the hoist control valve is in the SNUB position. A gauge connected to the rod end pressure tap while the hoist control valve is in the SNUB position will show the brake cooling system pressure, which is a result of the restriction in the coolers, brakes, and hoses. The maximum pressure in the circuit should correspond to the setting of the brake oil cooler relief valve.

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Text Reference

2

1

178

Two-stage hoist cylinders (1) are used to raise the body. Oil flows from the hoist control valve to the two hoist cylinders when the directional spool in the hoist control valve is not in HOLD. Check the condition of the body pads (2) for wear or damage. Hoist pilot pressure is required to lower the body with a dead engine. The towing pump can be used to provide the hoist pilot oil. To lower the body with a dead engine: 1. Move towing valve to TOW position. 2. Turn key ON. 3. Hold hoist lever in RAISE for 15 seconds. 4. Move hoist lever to HOLD and then FLOAT. 5. Press secondary steering switch and body will lower.

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Text Reference

Left Front

777F HOIST AND BRAKE COOLING SCHEMATICS From Torque Converter Lockup Clutch Pilot

Right Front Main Relief Dump Spool

From Tow Pump Circuit

Left Rear

From Torque Converter Lockup Clutch Pump From From Torque Brake Converter System

Lower / Float / Snub Solenoid

RAISE

Right Rear

Brake Cooling Pressure Test Port

SNUB

Cylinder Rod End Pressure Test Port

FLOAT Brake Cooling Relief

LOWER

179

This illustration shows the hoist hydraulic system in the HOLD position. The hoist pump pulls oil from the hydraulic tank through the suction screen located in the rear of the tank. Oil flows from the hoist pump to the hoist control valve. When the hoist control valve is in the HOLD, FLOAT, or SNUB position, all the hoist pump oil flows through the brake oil coolers located on the right side of the engine. Oil flows from the oil coolers, through the brakes, and returns to the hydraulic tank. NOTE: If the truck is equipped with the optional caliper type front brake system, the brake cooling pump is not installed and oil from the hoist pump will flow to only the rear brakes. A brake cooling relief valve is located in the hoist control valve. The relief valve limits the brake oil cooling pressure when the hoist control valve is in the HOLD, FLOAT, or SNUB position. The hoist valve uses torque converter lockup clutch pump oil as the pilot oil to shift the directional spool inside the hoist control valve. Oil flows from the lockup clutch pump to both ends of the hoist control valve.

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Text Reference

Pilot pressure is always present at both ends of the directional spool. Two solenoid valves are used to drain the pilot oil from the ends of the directional spool, which then allows the centering springs and the pressure on the opposite end of the spool to move the spool. When the RAISE solenoid is energized, the directional spool will move toward the RAISE solenoid. The RAISE and LOWER solenoid valves constantly receive approximately 300 millivolts at a frequency of 80 Hz from the Transmission/Chassis ECM when they are in any position except HOLD. The excitation, referred to as "dither," is used to keep the solenoids in a ready state for quick response. When the Transmission/Chassis ECM receives an input signal from the hoist lever sensor, the ECM sends an output signal current between 0 and 1.9 amps to one of the solenoids. The amount of current sent to the solenoid determines how much pilot oil is drained from the end of the directional spool and, therefore, the distance that the directional spool travels. The truck should normally be operated with the hoist lever in the FLOAT position. Traveling with the hoist in the FLOAT position will make sure the weight of the body is on the frame and body pads and not on the hoist cylinders. The hoist valve will actually be in the SNUB position. When the hoist control valve is in the RAISE position, pump supply oil flows to the head end of the hoist cylinders. Pump supply oil also flows to the dual stage signal spool and moves the spool to the left. When the dual stage signal spool moves to the left, pump supply oil is blocked from the LOWER relief valve, and the RAISE relief valve will limit the hoist system pressure. When the hoist control valve is in the LOWER (power down), FLOAT, or SNUB position, pump supply oil flows to the rod end of the hoist cylinders. Pump supply oil is blocked from the dual stage signal spool and the spring holds the spool in the right position. When the dual stage signal spool is in the right position, pump supply oil can flow to the LOWER relief valve, and hoist system pressure is controlled by the LOWER relief valve. An orifice plate is installed between the upper hose and the rod end port on both hoist cylinders. The orifice plate prevents cavitation of the cylinders when the body raises faster than the pump can supply oil to the cylinders (caused by a sudden shift of the load).

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3

1

9

Text Reference

4

6

5

2

8

7

180 BRAKE SYSTEM Two separate brake systems are used on the 777F. The two brake systems are the service/retarder brake system and the parking/secondary brake system. The parking/secondary brakes are spring engaged and hydraulically released. The service/retarder brakes are hydraulically engaged and spring released. The braking system is also equipped with a Brake ECM that controls the braking system functions, including the Automatic Retarder Control (ARC) and the Traction Control System (TCS). The air system on the previous model trucks has been completely removed. The main components in the braking system are: - Brake charging pump (1)

- Cab brake manifold (5)

- Brake cooling pump (standard oil cooled front brakes) (2)

- Service brake valve (6)

- Accumulator charging valve (3) - Brake accumulators (4)

- Brake oil filter (7) - Front slack adjuster (8) - Brake accumulator check valve (9)

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Text Reference

181

The rear brakes on the 777F Trucks are oil cooled. Shown is a cutaway illustration of an oil cooled brake assembly. The brakes are environmentally sealed and adjustment free. Oil continually flows through the brake discs for cooling. Duo-Cone seals prevent the cooling oil from leaking to the ground or transferring into the axle housing. The wheel bearing adjustment must be maintained to keep the Duo-Cone seals from leaking. The smaller piston (yellow) is used to engage the secondary and parking brakes. The parking brakes are spring engaged and hydraulically released. The larger piston (purple) is used to engage the service and retarder brakes. The service and retarder brakes are engaged hydraulically and released by spring force.

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Text Reference

Brake Actuation Pressure

777F STANDARD FRONT BRAKE

Disassembly Service Plug

182

The standard oil cooled front brakes are also environmentally sealed and adjustment free. The piston (yellow) is used to ENGAGE the service/retarder brakes. The front brakes do not have a second piston for the parking/secondary brakes. When the wheel is removed for service, the small plug at the lower left must be removed (the brake assembly is equipped with two similar plugs). Two 3/8 inch bolts must be installed at the plug locations to hold the brake discs and plates in position during wheel removal. The bolts ensure proper alignment of the teeth on the discs and plates during installation.

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Text Reference

777F OPTIONAL CALIPER DISC BRAKE Piston Bleed Valve Caliper

Carrier Lining

From Brake Cylinder

Disc

183

With the optional disc and caliper design brakes, the brake caliper assemblies are fastened to the spindle and do not rotate. The brake disc is fastened to the wheel and rotates with the wheel. Air can be bled from the front brakes through the bleed valves. During brake application, hydraulic oil from the brake cylinders forces the brake pistons against the brake carrier linings (brake pads). The brake linings are forced against the disc to stop the rotation of the wheel.

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Text Reference

3

2

1

184

3 2 1

185

The brake charging pump (1), the brake oil cooling pump (2), and the hoist pump (3) are mounted to the pump drive gear on the left rear side of the engine. The 777F brake system accumulators are charged by the brake charging pump, which supplies oil to the accumulator charging valve. The oil cooling pump sends oil to the oil coolers before the oil flows to the front and rear brakes for brake cooling. NOTE: The brake oil cooling pump is not installed on trucks with the optional caliper type front brakes.

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Text Reference

3

2 1

186

The brake system filter (1) is located on the left outer rear frame next to the left rear strut mount. The brake filter includes a filter bypass switch (2), which sends a signal to the Brake ECM if the filter is restricted. The Brake ECM sends a signal to the monitoring system, which illuminates the brake system-check indicator lamp. Brake system pressure can be checked at the tap (3) located in the hydraulic line to the accumulator charging valve.

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Text Reference

2

4 187 3

1

188 1

The accumulator charging valve (1) is located on the left side of the frame near the brake accumulators. The accumulator charging valve directs oil to the brake accumulators, brake oil coolers, and the tank. Once the accumulators are charged, the excess oil flow is sent to cool the brakes before returning to the tank. The Brake ECM monitors the pressure in the service brake accumulators with the brake accumulator pressure switch (2). If the pressure in the service brake accumulators is low, the Brake ECM will signal the monitoring system to turn on the brake system-check indicator lamp. A relief (3) valve limits the pressure in the brake charging circuit. The pressure tap (5) on the charging valve is used to check the oil pressure in the service brake accumulators.

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Text Reference

ACCUMULATOR CHARGING VALVE CUT-IN

To Brake Accumulators

Accumulator Oil Pressure Switch

Cut-In / Cut-out Spool

Relief Valve

Unloading Valve

To Brake Cooling System

From Brake Charging Pump

189

The accumulator charging valve maintains the pressure in the accumulators at a constant rate while the engine is running. If the machine has lost power or the hydraulic pump has failed, the pressure in the accumulators will permit several applications of the service brakes. This illustration shows the accumulator charging valve in the CUT-IN position. When the accumulator oil pressure decreases below a certain point, the accumulator charging valve reaches the cut-in pressure setting. The pressure decrease allows spring force to move the cut-in/cut-out spool to the left and oil flows to the right end of the unloading valve. The orifice in the unloading valve restricts the pump flow to the brake cooling system. Oil flow to the brake accumulators increases and the accumulators are charged. The accumulator oil pressure switch sends a signal to the Brake ECM to alert the operator when the brake oil pressure drops below the minimum operating pressure.

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Text Reference

ACCUMULATOR CHARGING VALVE CUT-OUT To Brake Accumulators

Accumulator Oil Pressure Switch

Cut-in / Cut-out Spool

Relief Valve

Unloading Valve

To Brake Cooling System

From Brake Charging Pump

190

This illustration shows the accumulator charging valve in the CUT-OUT position. When the accumulator oil pressure increases to the cut-out pressure setting, the increased pressure causes the cut-in/cut-out spool to move right against spring force. Oil at the right end of the unloading valve flows to the tank. Oil pressure on the left end of the unloading spool overcomes the decreased oil pressure on the right end of the spool and spring force. Most of the brake charging pump oil now flows to the brake cooling system. The check valve prevents high accumulator oil pressure from flowing to the brake cooling system. The accumulator charging valve remains in the CUT-OUT position until the pressure in the accumulators decreases to the cut-in pressure setting. The pressure relief valve regulates the oil pressure in the brake circuit. Any excess oil that is not required by the brake cooling system or the brake circuit is diverted back to the hydraulic oil tank. The pressure relief valve is set much higher than cut-out pressure and is used as a backup relief valve.

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Text Reference

191

1

1 2

192 1

1 2

There are the three brake accumulators for the 777F located on the left side of the frame. The service brake accumulators (1) and parking brake accumulator (2) are charged by the brake charging pump and supply the required oil flow to engage the front and rear service brakes and release the rear parking brakes. A check valve in the circuit between the parking brake accumulator and the service brake accumulators allows only the parking brake accumulator to be charged when using the electric brake release pump.

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3

Text Reference

2 193

1

4 194

1

3

2

The cab brake manifold (1) is mounted below the cab on the left upper frame. The cab brake manifold contains the ARC control solenoid (2) and the front service brake solenoid (3). The ARC control solenoid is part of the ARC system. The ARC system uses the rear service brakes and the front oil cooled brakes to automatically control the speed of the truck. The service brake pressure switch (4) is located near the cab brake manifold toward the front of the machine. The service brake pressure switch sends a signal to the Brake ECM when the service brakes are engaged. The Brake ECM will use the signal from the pressure switch to energize the stop lamp relay (located in cab) and turn on the brake lights. In a low pressure situation, the Brake ECM will signal the monitoring system to activate the brake system-check indicator.

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Text Reference

2 195 3

196 1

The service brake valve (1) is mounted below the floor of the operator’s cab. When the service brake pedal (2) is depressed, an internal spool directs oil flow from the service brake accumulators to the rear service brakes. The amount of oil flow to the front service brakes is determined by the Brake ECM based on a signal from the service brake pedal position sensor (3). The Brake ECM allows some oil from the brake accumulators to flow to the front brakes by controlling the position of the front brake solenoid located in the cab brake manifold. NOTE: If the front brake switch (optional front caliper type brakes only) is activated, the Brake ECM will command all oil to flow to the rear brakes.

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Text Reference

2

3

4 1

197

When the manual retarder lever (1) is activated, a PWM signal is sent to the Brake ECM. The Brake ECM sends a signal to the ARC solenoid and the front brake solenoid. The solenoids control the amount of oil flow to the service brakes based on the position of the retarder lever. If the ARC switch (2) is activated, the Brake ECM sends a signal to the ARC solenoid and the front brake solenoid. The solenoids control the amount of oil flow to the service brakes based upon the input signals that the Brake ECM receives from the engine speed sensor. NOTE: If the truck is equipped with the optional front caliper type brakes, the Brake ECM will command all oil to flow to the rear brakes when the retarder lever is moved or the ARC switch is activated. The optional engine brake switch (3) is also an input to the Brake ECM. The Brake ECM communicates the status of the brake switch to the Engine ECM via the Cat Data Link. The Engine ECM controls the compression brake application (if equipped). The front brake switch (4) is installed on machines with caliper type front brakes. When activated, the front brake switch sends a signal to the Brake ECM which allows the front brakes to be engaged when the brake pedal is depressed. When the front brake switch is in the OFF position, only the rear brakes will be engaged when the brake pedal is depressed.

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Text Reference

3

1 198

2

3

199

The 777F has two slack adjusters. The top illustration shows the rear slack adjuster (1). The rear slack adjuster is located above the rear differential. The bottom illustration shows the front slack adjuster (2). The front slack adjuster is located on the left strut frame support. The slack adjusters compensate for brake disc wear by allowing a small volume of oil to flow through the slack adjuster and remain between the slack adjuster and the brake piston under low pressure. The slack adjusters maintain a slight pressure on the brake piston at all times. Brake cooling oil pressure maintains a small clearance between the brake discs. The service brake oil pressure can be tested at the taps (3) located on top of the slack adjusters.

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Text Reference

BRAKE SLACK ADJUSTER Oil Flow To Brake Cylinder

Small Piston

Large Piston

Oil Flow From Brake Cylinder

From Wheel Brakes

From Wheel Brakes

To Wheel Brakes To Wheel Brakes

BRAKES RELEASED

BRAKES ENGAGED

200

This illustration shows sectional views of the slack adjuster when the brakes are RELEASED and ENGAGED. When the brakes are ENGAGED, oil from the brake cylinder enters the slack adjuster and the two large pistons move outward. Each large piston supplies oil to one wheel brake. The large pistons pressurize the oil to the service brake pistons and ENGAGE the brakes. Normally, the service brakes are FULLY ENGAGED before the large pistons in the slack adjuster reach the end of their stroke. As the brake discs wear, the service brake piston will travel farther to FULLY ENGAGE the brakes. When the service brake piston travels farther, the large piston in the slack adjuster moves farther out and contacts the end cover. The pressure in the slack adjuster increases until the small piston moves and allows makeup oil from the brake cylinder to flow to the service brake piston. When the brakes are RELEASED, the springs in the service brakes push the service brake pistons away from the brake discs. The oil from the service brake pistons pushes the large pistons in the slack adjuster to the center of the slack adjuster. Makeup oil that was used to ENGAGE the brakes is replenished at the brake cylinder from the makeup tank.

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Text Reference

The spring behind the large piston causes some oil pressure to be felt on the service brake piston when the brakes are RELEASED. Keeping some pressure on the brake piston provides rapid brake engagement with a minimum amount of brake cylinder piston travel. The slack adjusters can be checked for correct operation by opening the service brake bleed screw with the brakes RELEASED. A small amount of oil should flow from the bleed screw when the screw is opened. The small flow of oil verifies that the spring behind the large piston in the slack adjuster is maintaining some pressure on the service brake piston.

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Text Reference

2

1

201

The service brake bleed screw (1) is identified by an "S" on the brake anchor plate casting next to the screw. The parking brake bleed screw (2) is identified by a "P" on the casting. Another check to verify correct slack adjuster operation is to connect a gauge to the pressure tap on top of the slack adjuster and another gauge at the service brake bleed screw location on the brake anchor plate casting. With the service brake pedal depressed, the pressure reading on both gauges should be approximately the same. When the brakes are RELEASED, the pressure at the slack adjuster should return to zero. The pressure at the service brake bleed screw location should return to the residual pressure held on the brakes by the slack adjuster piston. If the slack adjuster residual pressure is too low, it could indicate a failed slack adjuster. High residual pressure may indicate a failed slack adjuster or warped brake discs. To check for warped brake discs, rotate the wheel to see if the pressure fluctuates. If the pressure fluctuates while rotating the wheel, the brake discs are probably warped and should be replaced. To check for brake cooling oil leakage, block the brake cooling ports and pressurize each brake assembly to a maximum of 138 kPa (20 psi). Close off the air supply source and observe the pressure trapped in the brake assembly for five minutes. The trapped pressure should not decrease.

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Text Reference

202

1

4 3

1

203 2

The parking brake valve (1) is located on the inside left frame rail behind the center cross member. The parking valve receives oil flow from the parking brake accumulator. Contained within the valve is a parking brake solenoid valve (2) and a purge solenoid valve (3). When the parking brake solenoid is energized by the Brake ECM, the parking brake valve directs oil flow through the TCS valve to release the rear parking brakes. There are no parking brakes on the front wheels. When the transmission shift lever is moved to PARK a signal is sent to the Brake ECM to engage the parking brakes. There is not a separate parking brake control switch. The secondary brake pressure switch (4) sends a signal to inform the Transmission/Chassis ECM that the secondary/parking brake is engaged. When the machine is shut down, the purge solenoid is energized by the Transmission/Chassis ECM and the purge valve drains the brake accumulators to tank.

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Text Reference

1 2

204

The parking brake pressure can be checked at the left parking brake tap (1) and at the right parking brake tap (2).

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Text Reference

205

The secondary brake pedal position sensor (arrow) is located on the back of the secondary brake pedal. The position sensor sends a signal to the Brake ECM indicating the position of the secondary brake pedal. The Brake ECM sends a signal to the parking brake solenoid which controls the secondary brake application at the rear brakes.

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Text Reference

206

The secondary steering/brake release/QuickEvac pump and motor are located on the front of the front frame crossmember as previously shown. The brake retract pump section (arrow) provides oil to release the parking brakes and hoist pilot oil for lowering the body on trucks with a dead engine.

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Text Reference

207

The diverter (towing) valve (arrow) is located on the left hoist cylinder frame support. The diverter valve is used to unlock the brakes for towing and must be manually shifted before towing. Once the valve is shifted, oil flow from the electric secondary steering/brake retract pump is directed to the parking brake valve to release the parking brake. To release the parking brakes for service work or towing, the electric motor on the pump is energized by the brake release switch located in the cab. When the key start switch is turned ON, the secondary steering system is energized for three seconds to check the system. Since the towing pump is driven by the same electric motor as the secondary steering pump, the diverter valve allows the towing pump oil to flow directly to the hydraulic tank during the secondary steering test. To shift the diverter valve, loosen the two diverter valve clamp bolts and slide the plate and the spool to the left. After the spool is shifted, tighten the diverter valve clamp bolts. When the electric motor is energized, supply oil can flow from the towing pump, through the diverter valve, to the parking brake valve. The brake release pump is also used to provide pilot oil to lower the body when the engine is off.

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Text Reference

BRAKE COOLING SYSTEM OIL COOLED FRONT BRAKES

Front Brakes

Hoist, Converter, and Brake Oil Coolers

Right

Left

From Brake Accumulator Charging Hoist Valve Valve

Rear Brakes

Screen

Right Screen

From Brake Cooling Pump

Left

Torque Converter Charging Filter Inlet Relief Valve

To Variable Speed Clutch Control To Hoist Pilot Signal Resolver

Lockup Clutch Valve

Outlet Relief Valve

Lockup Relief Valve

Lockup Clutch Filter

To TCS Converter Valve Scavenge Screen

208

This schematic shows the oil flow through the brake cooling system on the 777F Trucks with standard oil cooled front brakes. The brake cooling pump supplies oil to the brake coolers and the front and rear brakes. The brake cooling system also receives oil from the following components: - Hoist valve (in the HOLD, FLOAT, and SNUB positions) - Accumulator charging valve - Torque converter lockup clutch relief valve - Torque converter outlet relief valve The pressure in the brake cooling system is limited by a relief valve located in the hoist valve. The relief valve is usually needed only when the brake cooling oil is cold. When brake cooling oil is at operating temperature, the brake cooling oil pressure is usually much lower than the setting of the oil cooling relief valve. NOTE: On trucks equipped with the optional caliper type front brakes, the brake cooling system oil flows only to the rear brakes.

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Text Reference

2

1 209 3

The brake cooling pump (1) is a gear-type pump that is attached to the drive gear at the rear of the engine. The brake cooling pump is located between the hoist pump (2) and the brake charging pump (3). Oil flows from the brake cooling pump to the brake oil coolers. NOTE: The brake oil cooling pump is not installed on trucks with the optional caliper type front brakes.

210

The brake oil coolers (arrows) are located on the right side of the engine. Engine coolant from the water pump flows around the brake oil coolers and back to the cylinder block. The engine coolant transfers the heat from the brake oil system to the engine coolant. Oil from the brake cooling pump flows through screens (not shown) before flowing through the brake oil coolers.

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Text Reference

211

Shown is the left rear brake housing. Brake cooling oil pressure can be tested at the two taps (arrows) located in the brake cooling oil tubes. One tap is located on the brake cooling inlet tube and another tap is located on the brake cooling outlet tube. The pressure measured at the brake inlet tube (from the oil coolers) will always be higher than the pressure measured at the brake outlet tube. A brake oil temperature sensor is located in a brake oil cooling tube on the truck. The brake oil temperature sensor sends a signal to the Brake ECM indicating brake oil temperature. The Brake ECM will send a signal over the Cat Data Link, which informs the monitoring system to display the temperature on the brake temperature gauge. The most common cause of high brake cooling oil temperature is operating the truck in a gear range which is too high for the grade and not maintaining a high enough engine speed. The engine speed should be maintained at approximately 1900 rpm during long downhill hauls. Make sure the oil cooling relief valve is not stuck open. Also, make sure the pistons in the slack adjuster are not stuck and holding too much pressure on the brakes.

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Text Reference

BRAKE HYDRAULIC SYSTEM

Left Rear Brake

Secondary Brake Pedal Position Sensor

Diverter Valve

Parking Brake Solenoid

ECM

Relief Valve

Parking Brake Valve

Service Brake Pedal Position Sensor

Service Brake Valve

ARC Control

Purge Valve

Left Front Brake Cab Brake Manifold

M Secondary Pump

Parking Brake Accumulator Service Brake Accumulators

From TC Lockup Clutch Pump

Switch

TCS Valve Cut-In / Cut-Out Spool Unloading Valve Slack Adjuster

To Brake Cooling

Accumulator Charging Valve Relief Valve

Brake Filter

From TC Valve

Right Front Brake

Right Rear Brake

212

This schematic shows the major components of the brake system with the standard oil cooled front brakes. The front slack adjuster is not included on the optional caliper type front brake system. Oil is drawn from the hydraulic tank by the brake charging pump. Oil flows through the brake filter to the accumulator charging valve. The accumulator charging valve directs supply oil to the brake accumulators. The accumulator charging valve also controls the cut-in and cut-out pressure. When the accumulators are charged, the charging valve will direct excess pump flow to the brake cooling system. The service brake accumulators provide oil flow through the cab manifold to the service brake control valve. Oil flowing into the cab manifold also flows to the ARC control solenoid and front brake solenoid. When the operator depresses the service brake pedal, the service brake control valve directs pump flow to the rear service brakes to stop the truck. The front brakes are only engaged when the Brake ECM energizes the front brake solenoid. With the standard oil cooled front brakes, the Brake ECM determines when to energize the front brake solenoid when the service brake pedal is depressed. With the optional caliper type front brakes, the Brake ECM will energize the front brake solenoid when the front brake lockout switch in the cab is activated.

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Text Reference

The Brake ECM controls the modulation of the ARC solenoid and front brake solenoid, which controls truck braking when the ARC system is ON. Oil from the parking brake accumulator flows to the parking brake valve and the towing diverter valve. When the parking brake is activated, the supply oil for releasing the parking brakes is directed to the tank and the parking brakes are engaged by spring force. When the parking brake solenoid is energized (parking brake de-activated), the parking brake valve directs oil to the TCS valve. The pressure reducing valves in the TCS valve direct oil to release the parking brakes. The diverter valve, under normal operation, is closed and blocks the oil flow from the electric brake retract pump. If the truck is to be towed with a dead engine, the diverter valve must be shifted manually. When manually shifted, the diverter valve directs oil flow from the electric brake retract pump to the parking brake valve to release the rear brakes.

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Text Reference

BRAKE CONTROL MODULE SYSTEM DIAGRAM Cat Data Link

INPUTS

OUTPUTS

Key Start Switch Accumulator Oil Pressure Switch Brake Filter Bypass Switch TCS Test Switch

Secondary Brake Pedal Position Sensor Service Brake Pedal Position Sensor Retarder Lever Engine Speed Sensor

ARC ON /OFF Switch

Compression ON /OFF Switch Front Brake Lockout Switch

Left Rear Wheel Speed Sensor

ARC Control Solenoid Front Service Brake Solenoid Parking Brake Solenoid TCS Proportional Solenoid TCS Selector Solenoid

Right Rear Wheel Speed Sensor Brake Oil Temperature Sensor

213

Brake Electronic Control System The 777F Trucks are equipped with a Brake ECM for controlling the parking brake and front service brake applications, the ARC system, and the TCS. The following two possible arrangements can be installed on a truck: - ARC only - ARC and TCS The Brake ECM receives information from various input components such as the engine speed sensor, the service brake pedal position sensor, the ARC switch, and the wheel speed sensors. Based on the input information, the Brake ECM controls the front service brake application when the service brake pedal is depressed or the front and rear service brake application when the ARC system is activated. The Brake ECM also controls when the parking brakes should engage for the TCS and parking brake application when the parking brake is manually activated.

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Text Reference

Output components include the ARC solenoid, the front service brake solenoid, the TCS selector and proportional solenoids, and the parking brake solenoid. The compression brake switch is also an input to the Brake ECM. When the compression brake switch is activated, the Brake ECM sends a signal over the Cat Data Link to the Engine ECM. The Engine ECM controls the engine compression brake, which was covered earlier in the presentation.

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Text Reference

214

The Brake ECM (arrow) is located in the compartment at the rear of the cab. The Brake ECM performs the brake control functions, and controls the ARC system and TCS. The Brake ECM is an A4M1 module with two 70-pin connectors. The Brake ECM communicates with the Engine ECM, Transmission/Chassis ECM, and monitoring system over the CAT Data Link and can communicate with some attachments over the CAN Datalink.

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Text Reference

SERVICE / RETARDER BRAKE CIRCUIT BRAKES RELEASED

Service Brake Pedal Position Sensor To Rear Service Brakes ARC Solenoid

Service Brake Valve

From Service Brake Accumulat ors

Retarder Lever Brake ECM

Front Service Brake Solenoid

To Front Service Brakes

Front Brake Lockout Swit ch (Caliper Type Front Brakes)

Cab Manifold

215

When the service brake pedal is depressed, the service brake valve directs oil from the service brake accumulators to the rear brakes and sends a PWM signal to the Brake ECM via the service brake pedal position sensor. The Brake ECM then determines what signal to send to the front service brake solenoid based on the following conditions: 1. If the truck is equipped with the standard oil cooled front brakes, the Brake ECM signals the front service brake solenoid to direct oil from the service brake accumulators to the front and rear brakes. 2. If the truck is equipped with the optional caliper type front brakes, the Brake ECM receives a signal from the front brake lockout switch in the cab. If the lockout switch is OFF, the Brake ECM signals the front service brake solenoid to direct oil from the service brake accumulators to the front and rear brakes the same as the oil cooled front brakes. NOTE: Oil flow to the front and rear brakes may not be proportional. When the pedal is initially depressed, more oil is directed to the rear brakes. As the pedal is depressed farther more oil is sent to the front brakes in proportion to the rear until full front brake pressure is present at full pedal travel.

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Text Reference

3. If the truck is equipped with the optional caliper type front brakes, and the lockout switch is ON, the Brake ECM de-energizes the front service brake solenoid. Oil flow to the front brakes is blocked and only the rear brakes are used to stop the truck. The Brake ECM also de-energizes the ARC solenoid when the ARC switch in the cab is OFF and the manual retarder lever is in the NEUTRAL position. The manual retarder lever also controls the service brake application using the front brake solenoid and the ARC solenoid. When the retarder lever is moved, a PWM signal is sent to the Brake ECM. The Brake ECM then determines what signal to send to the ARC solenoid and front service brake solenoid based on the following conditions: 1. If the truck is equipped with the standard oil cooled front brakes, the Brake ECM signals the ARC solenoid and the front service brake solenoid to divide the oil flow from the service brake accumulators between the front and rear brakes. 2. If the truck is equipped with the optional caliper type front brakes, the Brake ECM de-energizes the front service brake solenoid. Oil flow to the front brakes is blocked and only the rear brakes are used to stop the truck with the retarder lever.

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Text Reference

AUTOMATIC RETARDER CONTROL (ARC) To Rear Service Brakes ARC Solenoid

Service Brake Valve

From Service Brake Accumulators

Brake ECM

Front Service Brake Solenoid

Engine Speed Sensor ARC ON/OFF Switch

To Front Service Brakes

Cab Manifold

216

Automatic Retarder Control (ARC) The ARC system receives signals from several switches and sensors. The main inputs to the Brake ECM for the ARC system are the ARC switch and engine speed sensor. The Brake ECM analyzes the various input signals and sends output signals to the ARC solenoid and front service brake solenoid. NOTE: If the truck is equipped with the optional front caliper type brakes, the Brake ECM will de-energize the front service brake solenoid when the ARC system is activated. The ARC system function is to modulate truck braking (retarding) when descending a long grade to maintain a constant engine speed. The ARC system engages the rear service brakes and the front oil cooled service brakes. If the ARC switch is moved to the ON position, the ARC system will be activated if the throttle pedal is not depressed and the parking/secondary brakes are RELEASED. The ARC system is disabled when the throttle is depressed or when the parking/secondary brakes are ENGAGED.

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Text Reference

The ARC is set at the factory to maintain a constant engine speed of 1938 (engine speed is programmable from 1838 to 1938 rpm). When the ARC initially takes control of retarding, the engine speed may oscillate out of the ± 50 rpm target, but the engine speed should stabilize within a few seconds. For proper operation of the ARC system, the operator needs only to activate the control with the ARC switch and select the correct gear for the grade, load, and ground conditions. The ARC system is designed to allow the transmission to upshift to the gear selected by the shift lever. After the transmission shifts to the gear selected by the operator and the engine speed exceeds 1938 rpm, the ARC system will apply the retarder as needed to maintain a constant engine speed. The ARC system also provides engine overspeed protection. If an unsafe engine speed is reached, the ARC will engage the brakes, even if the ARC switch is in the OFF position and the throttle is depressed. Trucks approaching an overspeed condition will sound a horn and activate a light. If the operator ignores the light and horn, the ARC will engage the retarder. If the engine speed continues to increase, the Transmission/Chassis ECM will either upshift (one gear only above shift lever position) or unlock the torque converter (if the shift lever is in the top gear position). The ARC also provides service personnel with enhanced diagnostic capabilities through the use of onboard memory, which stores possible faults, solenoid cycle counts and other service information for retrieval at the time of service.

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Text Reference

TRACTION CONTROL SYSTEM ( TCS)

INPUTS

OUTPUTS

Left Rear Wheel Speed Sensor

TCS Proport ional Solenoid

Right Rear Wheel Speed Sensor

TCS Select or Solenoid

TCS Test Swit ch Service Brake Pressure Swit ch

Cat Data Link

Transmission Out put Speed Sensor 1 Transmission Out put Speed Sensor 2

217

Traction Control System (TCS) The Traction Control System (TCS) uses the rear parking/secondary brakes (spring engaged and hydraulically released) to decrease the revolutions of a spinning wheel. The TCS allows the tire with better underfoot conditions to receive an increased amount of torque. The system is controlled by the Brake ECM and operates the same as the 777D TCS. The Brake ECM monitors the drive wheels through four input signals: one at each drive axle, and two at the transmission output shaft. When a spinning drive wheel is detected, the Brake ECM sends a signal to the selector and proportional valves which ENGAGE the brake of the affected wheel. When the condition has improved and the ratio between the right and left axles returns to 1:1, the Brake ECM sends a signal to RELEASE the brake.

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Text Reference

The service brake pressure switch provides an input signal to the Brake ECM from the Transmission/Chassis ECM through the CAT Data Link and performs the following two functions: 1. When the service brakes or retarder are ENGAGED, the TCS function is stopped. 2. The service brake pressure switch provides the input signal needed to perform a diagnostic test. When the TCS test switch and the retarder lever are ENGAGED simultaneously, the TCS will engage each rear brake independently. Install two pressure gauges on the TCS valve, and observe the pressure readings during the test cycle. The left brake pressure will decrease and increase. After a short pause, the right brake pressure will decrease and increase. The test will repeat as long as the TCS test switch and the retarder lever are ENGAGED. The TCS valve has left and right brake release pressure taps. When the proportional solenoid is ENERGIZED, Cat ET will show 68% when the brake is FULLY ENGAGED. NOTE: During the diagnostic test, the parking/secondary brakes must be released.

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Text Reference

218

Shown is the right rear wheel speed sensor (arrow) looking toward the rear of the truck. The TCS monitors the drive wheels through four input speed signals: one at each drive axle, and two at the transmission output shaft. The transmission output speed sensors monitor the ground speed of the machine and provide input signals to the Brake ECM through the CAT Data Link. The TCS uses the transmission output speed sensors to disable the TCS when ground speed is above 19.3 km/h (12 mph).

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Text Reference

2 1

3 3

219

The TCS valve is mounted inside the left frame rail toward the rear of the machine. Two solenoids are mounted on the valve. Electrical signals from the Brake ECM cause the selector solenoid valve (1) to shift and select either the left or right parking brake. If the selector valve shifts to the left parking brake hydraulic circuit, the control oil is drained. The left reducing spool of the control valve can then shift and engage the parking brake. The proportional solenoid valve (2) controls the volume of oil being drained from the selected parking brake control circuit. The rate of flow is controlled by a signal from the Brake ECM. The pressure taps (3) can be used to test the left and right brake release pressures when performing diagnostic tests on the TCS. At HIGH IDLE, the pressure at the taps in the TCS valve will be approximately 138 kPa (20 psi) less than the brake release pressure tested at the wheels. The pressure taps are also used to provide parking brake dragging information to the service technician. If the parking brakes are released, as sensed by the secondary brake pressure switch on the parking brake control valve, and parking brake pressure is below 3445 kPa (500 psi), a parking brake dragging event will be logged in the Brake ECM. The event can be viewed with Cat ET.

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Text Reference

TCS VALVE

ENGINE RUNNING / BRAKES RELEASED From Parking Brake Valve

From TC Lockup Clutch Pump

To Left Rear Brake

Brake Reducing Valve

Proportional Solenoid

Selector Solenoid Brake Reducing Valve

To Right Rear Brake

220

This illustration shows the TCS valve with the engine running and the brakes RELEASED. With the engine running, oil flows from the brake charging pump to the parking brake valve. When the operator moves the transmission lever out of the PARK position, the Brake ECM energizes the parking brake solenoid which directs oil flow to the TCS valve. In the TCS valve, oil flows through a screen and orifices to the selector solenoid and the brake reducing valves. When the TCS is not activated, the oil is blocked at the selector solenoid. Oil pressure moves the brake reducing solenoids to the left and oil from the brake charging pump is directed to the parking brakes. The parking brakes are RELEASED.

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Text Reference

TCS VALVE

ENGINE RUNNING / LEFT BRAKE ENGAGED To Left From Parking Rear Brake Brake Valve

From TC Lockup Clutch Pump

Brake Reducing Valve Proportional Solenoid

Selector Solenoid Brake Reducing Valve

To Right Rear Brake

221

This illustration shows the TCS valve with the engine running and the left brake ENGAGED. When signals from the sensors indicate that the left wheel is spinning 60% faster than the right wheel, the Brake ECM sends a signal to the selector solenoid valve and the proportional solenoid valve. The selector solenoid valve shifts up to open a passage between the right end of the left brake pressure reducing valve and the proportional solenoid valve. The torque converter lockup pump oil provides signal oil to the drain ball check which allows oil from the TCS valve to return to the tank. The proportional solenoid valve opens a passage from the selector solenoid valve to drain through the drain ball check. The proportional solenoid valve also controls the rate at which the oil is allowed to drain. Control circuit oil drains through the selector valve and enters the proportional valve.

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Text Reference

The reducing valve spool for the left parking brake shifts and blocks oil flow to the parking brake. Oil in the left parking brake control circuit begins to drain and the left parking brake begins to ENGAGE. The left brake orifice restricts the flow of oil from the parking brake valve. When the signals from the sensors indicate that the left wheel is no longer spinning, the Brake ECM stops sending signals to the selector solenoid and the proportional solenoid. The selector solenoid valve and proportional solenoid valve block the passage to drain and allow the control circuit pressure to increase. The left brake reducing valve spool shifts to the left and blocks the passage to drain. Parking brake oil is directed to the left parking brake and the brake is RELEASED.

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Text Reference

222

CONCLUSION This presentation has provided a basic introduction to the Caterpillar 777F Off-highway Truck. All the major component locations were identified and the major systems were discussed. When used in conjunction with the service manual, the information in this package should permit the technician to analyze problems in any of the major systems on these trucks.

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Text Reference

VISUAL LIST 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40.

Right side of 777F Truck Left side of 777F truck Front of 777F truck Rear of 777F truck Walk around inspection 10 hour daily maintenance checks Front wheel bearing oil level Suspension cylinder grease fitting Caliper disk brake linings Primary fuel filter Dual engine oil filters Scheduled Oil Sampling (SOS) coolant analysis tap Transmission filters Torque converter charging filter Fuel tank Final drive drain plug Differential Body up retaining pins Hydraulic tank Manual engine shutdown switch Battery disconnect switch Battery disconnect switch and auxiliary start receptacle Engine lockout control switch Battery and coolant sight glass location Steering system oil tank Air intake system components Engine oil level dipstick Windshield washer fluid level Operator's station Cab air filter 777F operator compartment Truck Production Management System (TPMS) Left side dash panel controls and switches Right side dash panel controls and switches Transmission shift lever Overhead console switches Brake pedals and throttle pedal Fuse panels Electronic system block diagram Instrument cluster

41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. 66. 67. 68. 69. 70. 71. 72. 73. 74. 75. 76. 77. 78. 79. 80.

Instrument cluster in front dash panel Indicator lamps and gauges Messenger display module Main menu selection Performance screen submenu Performance menu selection Totals menu selections Settings menu selection Service menu selection Service menu diagnostic events Service mode VIMS/advisor display Advisor introduction screen Advisor main screen Warning screens Advisor operator menu Advisor operator profile Advisor home menu selections Advisor operator menu selection Service menu submenus Advisor calibrations screen Advisor service menu - Diagnostics submenu Service menu - calibrations submenu Service menu - service parameters submenu Settings menu Settings menu - display setup Payload menu option Payload target and calculated gauge information Monitor menu option - four parameters Monitor: Parameter Screen 1 Grade menu option Grade value and truck image information Service mode option Service mode disabled option C32 engine with ACERT Technology Engine ECM system diagram Engine ECM Left intake air temperature sensor Crankshaft speed/timing sensor Cam speed/timing sensor

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Text Reference

VISUAL LIST 81. 82. 83. 84. 85. 86. 87. 88. 89. 90. 91. 92. 93. 94. 95. 96. 97. 98. 99. 100. 101. 102. 103. 104. 105. 106. 107. 108. 109. 110. 111. 112. 113. 114. 115. 116. 117. 118. 119. 120.

Loss of engine speed/timing signal Throttle position sensor Pre-lubrication (Quick Evac) pump Ether start system High coolant temperature derate C11-C32 engine intake manifold temperature derate Engine exhaust manifold temperature derate Low oil pressure derate Air inlet restriction derate Fuel temperature derate Fuel filter restriction derate Engine compression brake Engine compression brake hydraulic circuit - compression brake OFF Engine compression brake schematic ARC power and compression braking levels vs time Jacket water cooling system Cooling system components Cooling system flow Engine oil system Fuel priming switch Fuel transfer pump Differential fuel pressure switch Fuel pressure regulator Low pressure fuel system Injector trim codes Injector trim file Air filter restriction indicator Turbocharger inlet pressure sensor C32 engine turbochargers ATAAC cores Exhaust temperature sensors Turbocharger outlet pressure sensors Air induction and exhaust system 777F power train major components Power train electronic components Power train hydraulic system Torque converter hydraulic system Power train pump sections Torque converter - converter drive Torque converter - direct drive

121. Rear of torque converter 122. Torque converter screen 123. Lockup clutch modulating valve - torque converter drive 124. Lockup clutch modulating valve - direct drive 125. Torque converter outlet temperature sensor 126. Lockup clutch valve oil filter 127. Lockup clutch oil filter bypass switch 128. Lockup clutch relief valve 129. Torque converter charging filter 130. Torque converter filter S•O•S port 131. Transmission hydraulic system NEUTRAL 132. Transmission scavenge pump section 133. Transmission oil cooler 134. Transmission charge oil filters 135. Transmission modulating valves 136. Transmission clutch engagement chart 137. Transmission modulating valve - no commanded signal 138. Transmission modulating valve commanded signal below maximum 139. Transmission modulating valve commanded signal at maximum 140. Main relief valve 141. Rear axle components 142. Differential removed from rear axle housing 143. Transmission/Chassis control module system diagram 144. Transmission/Chassis ECM 145. Transmission shift lever circuits 146. Transmission output speed sensors 147. Engine speed sensor 148. Transmission oil level switch 149. Body up switch 150. Transmission/Chassis ECM - systems controlled by the ECM 151. 777F steering system major components 152. Oil level sight gauge 153. Steering system oil filter 154. Steering pump and control valve

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Text Reference

VISUAL LIST 155. 156. 157. 158. 159. 160. 161. 162. 163. 164. 165. 166. 167. 168. 169. 170. 171. 172. 173. 174. 175. 176. 177. 178. 179. 180. 181. 182. 183. 184. 185. 186. 187. 188.

Steering pump - low pressure standby Steering pump - maximum flow Steering disable valve Steering valve 777F HMU Electric secondary steering pump and motor Secondary pressure switch Steering hydraulic system schematicHOLD 777F hoist system major components Hoist lever Hoist lever, transmission sensor, and transmission shift lever sensor Hoist, converter, and brake hydraulic tank Rear of hoist, converter and brake hydraulic tank Hoist pump Hoist pump pressure tap Hoist control valve Hoist solenoid valves Hoist system pressure taps Hoist control valve - HOLD Hoist control valve - RAISE Hoist control valve - LOWER/POWER DOWN Hoist control valve - FLOAT Hoist control valve - SNUB Two-stage hoist cylinders 777F hoist and brake cooling schematic Brake system major components Oil cooled brake assembly (cutaway) 777F Standard front brake 777F optional caliper disc brake Brake charging pump Brake oil cooling pump Brake system oil filter Brake accumulator pressure switch Accumulator charging valve

189. 190. 191. 192. 193. 194. 195. 196. 197. 198. 199. 200. 201. 202. 203. 204. 205. 206. 207. 208. 209. 210. 211. 212. 213. 214. 215. 216. 217. 218. 219. 220. 221. 222.

Accumulator charging valve - CUT-IN Accumulator charging valve - CUT-OUT Service brake accumulators Parking brake accumulator Cab brake manifold Service brake pressure switch Service brake pedal Service brake valve Manual retarder lever Rear slack adjuster Front slack adjuster Brake slack adjuster sectional view Service brake bleed screw Parking brake valve Parking brake solenoid valve Left and right parking brake tap Secondary brake pedal position sensor Brake retract pump section Diverter (towing) valve Brake cooling system - oil cooled front brakes Brake cooling pump Brake oil coolers Rear brake housing Brake hydraulic system schematic Brake control module system diagram Brake ECM Service / Retarder brake circuit BRAKES RELEASED Automatic retarder control (ARC) Traction control system (TCS) Right rear wheel speed sensor TCS valve TCS valve - engine running / brakes released TCS valve - engine running / left brake engaged Model view - rear

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Text Reference

HYDRAULIC SCHEMATIC COLOR CODE Black - Mechanical connection. Seal

Red - High pressure oil

Dark Gray - Cutaway section

Red/White Stripes - 1st pressure reduction

Light Gray - Surface color

Red Crosshatch - 2nd reduction in pressure

White - Atmosphere or Air (No pressure)

Pink - 3rd reduction in pressure

Purple - Pneumatic pressure

Red/Pink Stripes - Secondary source oil pressure

Yellow - Moving or activated components

Orange - Pilot, charge, or Torque Converter oil

Cat Yellow - (R estricted usage) Identification of components within a moving group

Orange / White Stripes Reduced pilot, charge, or TC oil pressure

Brown - Lubricating oil

Orange Crosshatch - 2nd reduction in pilot, charge, or TC oil pressure.

Green - Tank, sump, or return oil

Blue - Trapped oil

Green / White Stripes Scavenge Oil or Hydraulic Void

HYDRAULIC SCHEMATIC COLOR CODE This illustration identifies the meanings of the colors used in the hydraulic schematics and cross-sectional views shown throughout this presentation.

Red Crosshatch - 2nd reduction in pressure Pink - 3rd reduction in pressure Red/Pink Stripes - Secondary source oil pressure Orange - Pilot, charge, or Torque Converter oil Orange / White Stripes Reduced pilot, charge, or TC oil pressure

Light Gray - Surface color

White - Atmosphere or Air (No pressure)

Purple - Pneumatic pressure

Yellow - Moving or activated components

Cat Yellow - (R estricted usage) Identification of components within a moving group

Blue - Trapped oil

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Green / White Stripes Scavenge Oil or Hydraulic Void

Green - Tank, sump, or return oil

Orange Crosshatch - 2nd reduction in pilot, charge, or TC oil pressure.

Red/White Stripes - 1st pressure reduction

Dark Gray - Cutaway section

Brown - Lubricating oil

Red - High pressure oil

Black - Mechanical connection. Seal

HYDRAULIC SCHEMATIC COLOR CODE

SERV1828 01/07 Handout No. 1

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Handout No. 2

Machine Daily Inspection Checklist Directions: Use this sheet and the Operation and Maintenance Manual when performing the daily inspection as part of the machine orientation lab exercise. Place a check in the blank after the task is performed.

_____

Back-up Alarm - Test

_____

Brake, Indicators, and Gauges - Test

_____

Braking System - Test

_____

Cooling System Level - Check

_____

Differential and Final Drive Oil - Check

_____

Engine Air Filter Service Indicator - Inspect

_____

Engine Oil Level - Check

_____

Engine Oil Level (Oil Renewal System) - Check

_____

Engine Oil Level (Oil Renewal System) - Log Additions

_____

Fuel Tank Water and Sediment - Drain

_____

Fuel System Water Separator - Drain

_____

Hoist, Converter, and Brake Tank Oil Level - Check

_____

Seat Belt - Inspect

_____

Secondary Steering - Test

_____

Steering System Oil Level - Check

_____

Transmission Tank Oil Level - Check

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Handout No. 3

Machine Maintenance Locations Place a check in the blank after locating the following maintenance items.

Filter Locations: _____

Brake oil filter

_____

Steering pump oil filter (case drain)

_____

Steering system oil filter

_____

Transmission oil filters

_____

Torque converter charge oil filter

_____

Lockup clutch oil filter

_____

Air conditioner filter

_____

Cab air filter

_____

Engine oil filters

_____

Engine air filters

_____

Engine crankcase breather

_____

Secondary fuel filter

_____

Primary fuel filter

_____

Fuel tank breather

_____

Torque converter breather

_____

Differential and final drive breather

Sampling Valve Locations:

Sampling Port Locations:

_____

Engine oil

_____

Differential and final drive

_____

Hoist, converter, and brake oil

_____

Front wheel

_____

Transmission oil

_____

Steering system oil

What is used to take oil samples of the differential, final drive, and front wheel? _________________________________________________________________

SERV1828 01/07

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Handout No. 4

Instrument Cluster Component Identification 10 8

12

11

13

14

9

15

16

17

7 15

6

10

5

5

18 19 20

20 X100 n/min

25

R

21 22

4 0

3

n/min

30 mph km/h

23 kPa psi

2

24 25

1 List the number of each gauge or indicator: Brake system check

Traction control system engaged

Power train system check

Retarder engaged

Action lamp

Engine coolant temperature gauge

Electrical system

Machine immobilizer

Body up

Throttle lock

Transmission in reverse

Engine rpm

High beam

Machine lockout active

Transmission oil temperature gauge

Park brake engaged

Secondary steering engaged

Check engine

Truck speed

Brake oil temperature gauge

LCD display window

Fuel level gauge

Primary steering loss

Active gear and direction

Service hour meter

SERV1828 01/07

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Engine Component Identification _____ Fuel injectors Function: Location: _____ Coolant temperature sensor Function: Location: _____ Fuel pressure sensor Function: Location: _____ Intake manifold temperature sensors Function: Location: _____ Atmospheric pressure sensor Function: Location: _____ Turbo outlet (boost) pressure sensors Function: Location:

Handout No. 5

SERV1828 01/07

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Engine Component Identification (continued) _____ Engine oil pressure sensor Function: Location: _____ Speed/timing sensors Function: Location: _____ Engine ECM Function: Location: _____ Ground level shutdown switch Function: Location: _____ Secondary fuel filter Function: Location: _____ Primary fuel filter Function: Location:

Handout No. 6

SERV1828 01/07

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Engine Component Identification (continued) _____ Exhaust temperature sensors Function: Location: _____ Oil level switch Function: Location: _____ Fuel temperature sensor Function: Location: _____ Differential fuel pressure switch Function: Location: _____ Engine compression brake assemblies Function: Location: _____ Air filter restriction sensors Function: Location:

Handout No. 7

SERV1828 01/07

- 250 -

Power Train Component Identification _____ Pump group Function: Location: _____ Transmission oil filters Function: Location: _____ Lockup clutch relief valve Function: Location: _____ Lockup clutch oil filter Function: Location: _____ Lockup clutch modulating valve Function: Location: _____ Torque converter outlet relief valve Function: Location:

Handout No. 8

SERV1828 01/07

- 251 -

Power Train Component Identification (continued) _____ Torque converter inlet relief valve Function: Location: _____ Torque converter charge filter Function: Location: _____ Torque converter outlet temperature sensor Function: Location: _____ Transmission main relief valve Function: Location: _____ Transmission modulating valves Function: Location: _____ Transmission oil cooler Function: Location:

Handout No. 9

SERV1828 01/07

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Power Train Component Identification (continued) _____ Transmission hydraulic oil temperature sensor Function: Location: _____ Transmission/Chassis ECM Function: Location: _____ Engine speed sensor Function: Location: _____ Torque converter oil temperature sensor Function: Location: _____ Transmission input speed sensor Function: Location: _____ Transmission output speed sensors Function: Location:

Handout No. 10

SERV1828 01/07

- 253 -

Steering System Component Identification _____ Steering pump Function: Location: _____ Steering valve Function: Location: _____ Steering disable valve Function: Location: _____ HMU Function: Location: _____ Steering cylinders Function: Location: _____ Secondary steering pump Function: Location:

Handout No. 11

SERV1828 01/07

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Steering System Component Identification (continued) _____ Steering tank Function: Location: _____ Primary steering pressure switch Function: Location: _____ Secondary steering pressure switch Function: Location:

Handout No. 12

SERV1828 01/07

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Hoist System Component Identification _____ Hoist pump Function: Location: _____ Hoist control valve Function: Location: _____ Hoist, converter, and brake hydraulic tank Function: Location: _____ Hoist cylinders Function: Location: _____ Hoist lever position sensor Function: Location: _____ Hoist raise solenoid valve Function: Location:

Handout No. 13

SERV1828 01/07

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Hoist System Component Identification (continued) _____ Hoist lower solenoid valve Function: Location: _____ Brake cooling relief valve Function: Location:

Handout No. 14

SERV1828 01/07

- 257 -

Brake System Component Identification _____ Brake charging pump Function: Location: _____ Brake cooling pump Function: Location: _____ Accumulator charging valve Function: Location: _____ Brake accumulators Function: Location: _____ Cab brake manifold Function: Location: _____ Brake oil filter Function: Location:

Handout No. 15

SERV1828 01/07

- 258 -

Brake System Component Identification (continued) _____ Front slack adjuster Function: Location: _____ Rear slack adjuster Function: Location: _____ Service brake valve Function: Location: _____ Retarder lever Function: Location: _____ Parking brake valve Function: Location: _____ TCS valve Function: Location:

Handout No. 16

SERV1828 01/07

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Brake System Component Identification (continued) _____ Service brake pedal position sensor Function: Location: _____ Secondary brake pedal position sensor Function: Location: _____ Brake retract pump Function: Location: _____ Diverter (towing) valve Function: Location: _____ Brake oil coolers Function: Location: _____ Brake ECM Function: Location:

Handout No. 17

SERV1828 01/07

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Brake System Component Identification (continued) _____ Accumulator oil pressure switch Function: Location: _____ TCS test switch Function: Location: _____ ARC switch Function: Location: _____ Brake compression switch Function: Location: _____ Front brake lockout switch Function: Location: _____ Rear wheel speed sensors Function: Location:

Handout No. 18

Normal

P

R N

3

2

1

Payload

Settings

Service

Operator

03:55:46 07/7/2006 0%

P

OK

SERV1828 01/07 - 261 Handout No. 19

Inputs

Fuel Temp Sensor

Differential Fuel Pressure Switch

Fuel Pressure Sensor J2 (ENGINE) CONNECTOR

J1 (MACHINE) CONNECTOR

Air Conditioning Status

Right Air Filter Restriction (Turbo Inlet Right)

Left Air Filter Restriction (Turbo Inlet Left)

Rockford Fan Speed Sensor (Attachment)

Ground Level Shutdown Switch

ORS Level Relay ( at t achment )

Back-up Throttle Switch

Throttle Pedal Position Sensor

Key Start Switch

Outputs Inputs

Rockford Fan Solenoid ( At t achment )

Ether Start Relay

ORS Solenoid (Attachment)

CAT Data Link

- 262 -

Oil Level Switch

Exhaust Temperature Sensors (4)

Atmospheric Pressure

Engine Oil Pressure

Left Turbo Outlet Pressure Sensor

Right Turbo Outlet Pressure Sensor

Coolant Temperature Sensor

Left Intake Manifold Temperature Sensor

Right Intake Manifold Temperature Sensor

Timing Cal Probe Connector

Speed Sensor No. 2 (Cam)

Speed Sensor No. 1 (Crank)

Right Bank (Even) Engine Retarder Solenoids 066-8391 (Connector PN) Outputs

Left Bank (Odd) Engine Retarder Solenoids 066-8391 (Connector PN)

MEUI Injectors (12) 7E6513

ENGINE ECM SYSTEM DIAGRAM

SERV1828 01/07 Handout No. 20

Secondary Steering Motor State

Secondary Steer Test Switch

Engine Speed Sensor

Autolube Pressure Sensor

Body Up Switch

Inclinometer

Head Lamp Sense

Lockup Clutch Filter Bypass Switch

Transmission Solenoids 1-7

Start Relay

Backlight Intensity

Machine Lockout Lamp

Starter Lockout Lamp

Secondary Steering Relay

Backup Lamp Relay

Stop Lamp Relay

Autolube Relay

Back-up Alarm

Secondary Steering / QuickEvac / Prelube Relay

Hoist Lower Solenoid

Hoist Raise Solenoid

Service Brake Accumulator Bleed Solenoid Lockup Clutch Solenoid

Steering System Disable Solenoid

OUTPUTS

- 263 -

Service Brake Pressure Switch

Secondary Brake Pressure Switch

Secondary Steering Pressure Switch

Location Codes

Transmission Oil Level Switch

Transmission Output Speed Sensor 2

Fuel Level Sender

Transmission Charge Filter Bypass Switch Transmission Output Speed Sensor 1

Alternator R-Terminal

Hoist Lever Position Sensor

Shift Lever Position Sensor

Transmission Input Speed Sensor

Primary Steering Pressure Switch

QuickEvac Service Tool Input

Drive Gear Select Switches

Transmission Oil Temperature Sensor

Torque Converter Oil Temperature Sensor

Starter Lockout Switch

Machine Lockout Switch

Key Start Switch

INPUTS

Cat Data Link

TRANSMISSION / CHASSIS CONTROL MODULE SYSTEM DIAGRAM

SERV1828 01/07 Handout No. 21

Torque Converter Outlet Relief Valve

Torque Converter

To Brake Cooling

Lockup Clutch Valve Filter

To To Hoist Pilot Traction Signal Control Resolver Pilot

Torque Converter Inlet Relief Valve

Torque Converter Charge Filter

Lockup Valve

To Variable Speed Clutch Control

Transmission Oil Level Switch

Lockup Clutch Relief Valve

POWER TRAIN HYDRAULIC SYSTEM

Transmission

Hydraulic Controls

To Brake Cooling

Transmission Charge Filters

SERV1828 01/07 - 264 Handout No. 22

Secondary Pressure Switch

Secondary Steering Primary Relief Valve Secondary Steering Pump

M

Load Sensing Valve

Steering Disable Valve

Transmission Chassis ECM

Steering Filter

Steering Valve

Secondary Steering Back-up Relief Valve

HMU

Primary Steering Pressure Switch

LOW PRESSURE STANDBY

STEERING HYDRAULIC SYSTEM

Crossover Relief Valves

Case Drain Filter

Swashplate Piston

Actuator Piston

Flow Compensator

Piston Pump and Load Sensing Controller

Primary Steering Back-up Relief Valve

Pressure Reducing Valve

SERV1828 01/07 - 265 Handout No. 23

Right Rear

Left Rear

Brake Cooling Pressure Test Port

From Torque Converter Lockup Clutch Pump From From Torque Brake Converter System

From Tow Pump Circuit

From Torque Converter Lockup Clutch Pilot

Cylinder Rod End Pressure Test Port

LOWER

FLOAT

SNUB

RAISE

Lower / Float / Snub Solenoid

Main Relief Dump Spool

Brake Cooling Relief

777F HOIST AND BRAKE COOLING SCHEMATICS Right Front

Left Front

SERV1828 01/07 - 266 Handout No. 24

Parking Brake Valve

Parking Brake Solenoid

TCS Valve

From TC Lockup Clutch Pump

Secondary Pump

M

Diverter Valve

Parking Brake Accumulator

Brake Filter

From TC Valve

To Brake Cooling

Unloading Valve

Service Brake Accumulators

Relief Valve

Cut-in / Cut-out Spool

Service Brake Valve

Relief Valve

Accumulator Charging Valve

Switch

Cab Brake Manifold

ARC Control

Right Front Brake

Left Front Brake

ECM

Secondary Brake Pedal Position Sensor

Service Brake Pedal Position Sensor

- 267 -

Right Rear Brake

Slack Adjuster

Left Rear Brake

Purge Valve

BRAKE HYDRAULIC SYSTEM

SERV1828 01/07 Handout No. 25

SERV1828 01/07

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Handout No. 26

Posttest 1. When the engine lockout mode is activated, which of the following conditions exist: A. B. C. D.

engine starter is disabled secondary steering is disabled prelube function is disabled All of the above

2. The air conditioner filter is located: A. B. C. D.

on the left side of the cab on the right side of the cab on the front of the cab on the rear of the cab

3. The monitoring system includes how many warning categories A. B. C. D.

2 3 4 5

4. How many main menus are available for navigation on the Messenger menu screen? A. B. C. D.

3 4 5 6

5. Which of the following Messenger menus is used to determine when scheduled maintenance is required? A. B. C. D.

Performance menu Totals menu Settings menu Service menu

6. What information is NOT displayed when viewing diagnostic events on the Messenger display panel? A. B. C. D.

SRC (Source ID) Code OCC (number of occurrences) Parameter

SERV1828 01/07

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Handout No. 27

Posttest (continued) 7. When a "pop-up" warning screen is displayed on the Advisor display, which of the following is true? A. B. C. D.

Acknowledging the warning will clear the warning from the ECM's memory Acknowledging the warning will only clear the warning from the Advisor screen If the warning is acknowledged the warning no longer remains active None of the above

8. The calibrations menu in the Advisor Monitoring System allows calibration of which of the following: A. B. C. D.

truck payload injectors pressure sensors hoist solenoid valve

9. The monitor menu option in the Advisor Monitoring System allows the user to view how many parameters at one time? A. B. C. D.

1 2 3 4

10. Each compression brake assembly controls how many cylinders? A. B. C. D.

1 2 3 4

11. When the Engine ECM commands a MEDIUM braking level, the compression brake is activated for how many cylinders? A. B. C. D.

4 6 8 12

12. Pilot oil used to actuate the hoist solenoid valves is supplied by the: A. B. C. D.

lockup clutch valve oil circuit parking brake release filter hoist pump pressure reducing valve

SERV1828 01/07

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Handout No. 28

Posttest (continued) 13. The lockup clutch relief valve allows oil to flow to the _______________ when the lockup clutch valve circuit oil pressure is too high? A. B. C. D.

transmission hydraulic tank hoist, converter, and brake hydraulic tank steering circuit brake cooling circuit

14. Which of the following components is located on top of the transmission planetary gears? A. B. C. D.

Transmission main relief valve Transmission modulating valves Transmission hydraulic oil temperature sensor All of the above

15. Which of the following sensors checks the speed of the drive shaft to the speed of the engine? A. B. C. D.

Engine speed sensor Transmission input speed sensor Transmission output speed sensors Torque converter output speed sensor

16. When the machine lockout switch is activated, which of the following actions occurs? A. B. C. D.

HMU oil flow is blocked Steering pump is disabled Steering disable solenoid valve is energized All of the above

17. Which of the following is not installed on trucks with the optional caliper type front brakes? A. B. C. D.

Brake cooling pump Brake oil coolers Brake cooling relief valve All of the above

18. The ARC system uses the rear service brakes and the ______________________ to automatically control truck speed. A. B. C. D.

TCS parking brakes front caliper type brakes front oil cooled brakes

SERV1828 01/07

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Handout No. 29

Posttest (continued) 19. The front service brake solenoid directs oil to the front service brakes. What component directs oil to the rear service brakes? A. B. C. D.

Service brake valve ARC solenoid Diverter valve Both A and B

20. Oil is provided to the diverter valve by the: A. B. C. D.

brake cooling pump service brake accumulators parking brake accumulator hoist pump

SERV1828 01/07

Posttest Answer Key 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20.

D A C C B D B A D B C A D D B C A D D C

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Handout No. 30