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COURSE REFERENCE MATERIALS

773D Off highway Truck

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Service Training 773D Off highway Truck

Table of Contents 773D OHT Features and Specifications .................................

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Service Training 773D Off highway Truck

773D OHT Features and Specifications RATED PAYLOAD Body Struck Capacity Heaped 3:1 Heaped 2:1 (SAE) Heaped 1:1

50.00 Tons (45.4 MetricTons) 26.6 Cubic Meters 32.4 Cubic Meters 35.2 Cubic Meters 43.3 Cubic Meters

ENGINE

CAT 3412E (65° V-12 Turbocharged Aftercooled HEUI with 137mm (5.4") bore and 152mm (6.0")stroke.)

At 79 to 94 Deg. C High idle RPM Low idle RPM Stall Speed

2285630 635 + 30 - 10 1825665

Displacement

27.0 Litres (1649cu.in.)

Flywheel Power

485 kw (650HP)

TRANSMISSION

Caterpillar seven speed electronically controlled automatic transmission with seven FWD & one REV. First gear has both torque converter & direct drive and Reverse gear only torque converter drive and 2 to7 gears are direct drive.

Forward speed First gear Forward speed Seventh gear Reverse gear speed

9.6 KMPH 63.4 KMPH 11.6 KMPH

Converter out-let pressure Trans. Charging pump flow Trans. Scavenging pump flow

45 to75 psi. 160 lpm at 400 psi and 1800RPM 200 lpm at 10 psi and 1800RPM

Transmission oil pressure

500 psi (max) At high idle rpm in all gears 360 psi (min) At low idle rpm in R-N-1

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Transmission lube oil pressure

2.5 to 10 psi At 1000 RPM 25 to 40 psi At high idle RPM

Transmission lock-up pressure Conv. To LU LU To Conv

250 610 psi 1610 630 RPM 1399 6 30 RPM

FINAL DRIVE Differential reduction ratio Final drive reduction ratio Total reduction

3.64:1 4.80:1 17.8:1

HYDRAULIC SYSTEM

Twin ,Two stage hydraulic cylinders mounted out side main frame, power raise in both stages and power down in second stage.

Pump flow Relief pressure (Raise) Relief pressure (Lower) Relief pressure (Float) Body Raise time (High idle) Body Lower time (Float) Body Lower time (Power down)

490 lpm at 1000 psi and 2100 RPM 2500 675 psi 500 6 50 psi 250 psi(max) 9.5 Seconds 14.2 Seconds 12.5 Seconds

STEERING SYSTEM

Separate hydraulic system with two double acting cylinders. Front suspension cylinders act as king pins. Automatic electrical supplement steering is standard.

Steering angle Turning circle Dia. Front wheels Vehicle clearance circle Dia. Primary steering pressure Secondary steering pressure Stand by pressure Front wheels alignment Pump discharge at max. stroke

31 Deg. 22.0m 24.0m 3085650 psi at 2000 RPM 2200645 psi 475650 psi at high idle RPM 58.7 mm (toe out) 150 lpm at stand by pr. And at 2100 RPM

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Service Training 773D Off highway Truck

SUSPENSION SYSTEM

Independent self contained oil pneumatic suspension cylinders on each wheel. Rear sway bar is attached to frame and differential housing to minimize lateral sway.

Effective cylinder stroke (Front) Effective cylinder stroke (Rear) Rear axle oscillation (max)

209mm 149mm + 8 Deg.

BRAKE SYSTEM

Front brakes are caliper disc type actuated by air over hydraulic pressure, operator can switch off if not needed.

Braking surface Front

1395 sq. cm Rear service/retarder brakes are oil cooled disc brakes actuated by air over hydraulic pressure and the parking brakes are applied by spring force and released by oil pressure. The emergency brakes are applied on all four wheels; At front by the air over hydraulic pressure and at rear by the spring force.

Braking surface Rear

61264 sq. cm.

Brake cooling pressure

25 psi (max) at high idle RPM 2 psi (min) at 1000 RPM

Parking brake retract pressure

680630 psi at high idle RPM 650 psi (min) at low idle RPM

Brake pump flow (Gear) Brake pump flow (electrical)

97 lpm at 800 psi and 2100 RPM 19 lpm at 1800 RPM

TYRES

21.00 X 35.00 - 36 PR E4

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Service Training 773D Off highway Truck

SERVICE REFILL CAPACITIES

(IN LITRES)

Fuel Tank Cooling system Crank case Differential & Final Drive Steering Tank Steering System Brakes, Hoist & Hydraulic Tank Brake & Hoist System Transmission / Converter Sump Transmission System

700 137 68 140 34 56 133 277 53 72

OPTIONALS

Air Conditioner, Body Liners, Fast Fuel Filling, Exhaust Muffler, Tachograph, Tool Kit, Auto Fire Suppression Kit, Auto Lubrication Kit, Wind Shield Washer

WEIGHT DISTRIBUTION Total Empty Weight Chassis with Hoists Body Empty

37,772 kg 28,772 kg 9,000 kg

Empty Weight Distribution Front Axle 47.30% Rear Axle 52.70%

17,866 kg 19,906 kg

Loaded Weight Distribution Front Axle 33.3% Rear Axle 67.7%

27,682 kg 55,499 kg

Total Gross Weight

83,131 kg

DIMENSIONS Wheel Base Length Width at body Width at rear tyres Height with body fulley lifted Ground clearance Height with body on the frame

4191 mm 9210 mm 4398 mm 4418 mm 8736 mm 540 mm 4342 mm

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Service Training 773D Off highway Truck

General Description Of Power Train Systems

The power train is made up of four basic systems. The following systems are the four systems: Power Train Electronic Control Module Torque Converter Transfer Gears and Transmission Differential and Final Drives The four basic systems have a hydraulic connection, an electrical connection, a magnetic connection, or a mechanical connection. The operation of the power train begins at the Power Train Electronic Control Module (Power Train ECM). The Power Train ECM receives information of the selected speed of operation through the shift lever switch in the electrical system. The Power Train ECM uses the information from several switches and sensors in the electrical system to control the power train hydraulic system. This is done by energizing the appropriate solenoids. The torque converter has a lockup clutch for direct drive and a one-way clutch for torque converter drive mode. During the torque converter drive mode, the torque converter hydraulically drives the transmission. The torque converter is fastened directly to the flywheel of the engine.

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Service Training 773D Off highway Truck

The basic components of the transmission hydraulic control group are downshift solenoid, upshift solenoid, pressure control valve, selector valve and rotary actuator. The solenoids are the connection between the electrical and hydraulic systems. The solenoids are activated electrically and send oil to the rotary actuator. The actuator turns the rotary selector spool in the selector valve which sends pilot oil to the pressure control valve. The pressure control valve then sends oil at the correct rate to smoothly engage the correct clutches in the transmission. The transmission (3) has seven forward speeds and one reverse speed. The selection of speed is done manually, in REVERSE, NEUTRAL and FIRST. The selection of SECOND through SEVENTH speeds is done automatically. REVERSE is torque converter drive only. FIRST has both a torque converter drive and a direct drive. SECOND through SEVENTH speeds are direct drive only with a very short time of converter drive during transmission clutch engagement to make shifts smooth. The transmission output shaft is fastened directly to the differential and bevel gear (1). The differential and bevel gear are fastened directly to the rear axle housing. After the transmission and torque converter are connected, power can now be supplied from the engine through the torque converter and transmission to the differential. The rear axles mechanically connect the differential to the final drives. The final drives are connected to the rear wheels. Power is then sent to the tires.

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Service Training 773D Off highway Truck

Power Train ECM

Brief Summary of Operation

1. The shift lever switch selects the desired speed and direction. 2. The transmission speed sensor magnetically measures tne transmission speed. 3. The Power Train ECM determines the proper moment for shifting by using the signals from the transmission speed sensor, tne shift lever switch and the transmission gear switch. The Power Train ECM activates the solenoids in order to make shifts. 4. The hoist control position sensor prevents any reverse operation of the transmission during the raise operation of the dump body. The hoist control position sensor also prevents any reverse operation of the transmission during the lowering operation of the dump body. The dump body position sensor will signal the limiting function on the gears. This limits the speed of the machine while the dump body is up.

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5. The switch for the parking and secondary brake and the retarder and service brake switch send input signals to the Power Train ECM. When the secondary parking brake switch or the retarder and service brake switch are activated, the antihunt timer is deactivated. When the service brake and retarder switch is activated, the Power Train ECM will allow rapid speed shifts. 6. When an upshift solenoid or a downshift solenoid is activated, pressure oil is sent to the rotary actuator. The rotary actuator turns the rotary selector spool. This sequence causes the correct pair of clutches to be engaged for the next desired speed. 7. The transmission hydraulic control will individually control the maximum pressure in each clutch. The transmission hydraulic control will individually modulate each clutch in order to control the fill time and the release time. 8. When the lockup clutch solenoid is activated, pressure oil is sent to the modulation reduction valve of the lockup clutch valve. The oil engages the lockup clutch of the torque converter for direct drive. 9. The transmission gear switch tells the Power Train ECM the engaged gear of the transmission. The transmission gear switch is mechanically turned by the rotary selector spool. 10. The Power Train ECM uses the Caterpillar Data Link to communicate with the Caterpillar Monitoring System. The Caterpillar Monitoring System informs the operator of the transmission gear that is actually engaged.

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Power Train Hydraulic System Block Diagram

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Service Training 773D Off highway Truck

Torque Converter In the converter the impeller is driven by the engine flywheel. The turbine is connected to the output shaft. The lock up clutch permits the machine to operate in the direct drive. The one way clutch holds the stator when the torque converter is in converter drive mode. The oil for the torque converter comes from the inlet relief valve of the transmission selector and pressure control valve. The impeller directs the oil to the blades of the turbine and causes the turbine to rotate. The oil leaving the turbine is directed to the stator causes the stator to try to turn in the opposite direction. This movement of the stator causes the rollers of the one way clutch to move between the stator and the carrier for the stator. This locks the stator and directs the oil from the turbine to the impeller. A small portion of the oil goes through the outlet passage of the converter. The oil which is redirected onto the impeller has energy and flows in the direction of the impeller, multiplies the torque output of the converter. As the speed of the turbine increases with impeller the directed oil from the turbine turns the stator in the same direction of the turbine. Due to this the cam of the one way clutch turns causing the rollers to move out from the wedged condition in the tapered openings. The mechanical connection between the cam and the race is broken. At this condition the stator and the cam turn freely and the stator does not send the oil back to the impeller, simultaneously due to the increased speed of the turbine the power train ECM sends signal to the lock up solenoid for supplying the pressurized oil to the lock up piston to mechanically connect the engine and the turbine (Isolating the converter mode function) for direct drive operation. The drive shaft connects output shaft of the torque converter to the transfer gears whose driven gear is connected to the input of the planetary transmission.

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One-way Clutch

Detail of One way clutch (10) Cam (11) Rollers (12) Spring (13) opening (14) Race

Direct Drive

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Torque Converter Drive

Releif Valve (Torque Converter Outlet)

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Lockup Clutch and Solenoid Valve (Torque Converter)

A part of the delivered oil from the transmission charging pump enters the lockup clutch & solenoid valve at the pressure reduction valve which sends the oil to 1. Pilot passage up to the solenoid valve and 2. The supply passage of modulation reduction valve. (In the pressure reduction valve the incoming oil flows through an orifice, opening the ball check valve, to the slug chamber at the end of the valve and the pressurized oil acts against the spring of the spool, moves the spool to close the pilot passage and open the drain passage. This controls the pressure of the pilot oil). The pump supply oil to the modulation reduction remains full at pump pressure. The power train ECM energizes the lock up clutch solenoid when the direct drive is necessary. Due to this passage in the solenoid valve opens, the incoming oil pushes the shuttle valve ball and closes the drain passage and enters the top of the selector piston. The pressure of this oil moves the modulation valve and allows the pump oil to flow to the lock up clutch and gradually increases the pressure on the lock up piston to change the converter drive to direct drive.

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Transmission Description The Power Train ECM will activate the lockup clutch solenoid when direct drive is neccessary. When the lockup clutch solenoid is activated, the lockup clutch is hydraulically engaged. The rotating housing of the torque converter becomes mechanically connected to the output shaft of the torque converter through the lockup clutch. The drive shaft mechanically connects the torque converter to the transfer gears. The transfer gears are fastened directly to the transmission. When the lockup clutch is not activated, the torque converter drives the transmission hydraulically. The upshift solenoid and the downshift solenoid hydraulically activate the rotary actuator of the transmission. Movement of the rotary actuator mechanically selects the position of the rotary selector spool. The flow through the rotary selector spool hydraulically activates the correct valves in the pressure control valve. These valves engage the correct transmission clutches. This mechanically connects the transmission input shaft to the output shaft and to the differential. The transmission will not drive the output shaft unless power is flowing through the torque converter. The power that is flowing through the torque converter can be hydraulic or mechanical. The transmission has forward speeds and one reverse speed. The selection of reverse, neutral or first speed is done manually. The selection of second speed through the highest speed is done automatically. Reverse uses only the torque converter drive mode. First speed has both a torque converter drive and a direct drive. All speeds above first speed use the direct drive. The torque converter will be in torque converter drive for a short time during transmission shifts. This provides smoother engagement of the transmission clutch. The transmission output shaft is fastened directly to the differential and the bevel gear. The differential and the bevel gear are fastened directly to the rear axle housing. Power is supplied from the engine to the torque converter. Power goes from the torque converter to the transfer gears. The power then goes to the transmission. If the transmission is in gear, power flows from the transmission to the differential. The rear axles mechanically connect the differential to the final drives. The final drives are connected to the rear wheels. Power is then sent to the tires.

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When the transmission is in the correct speed position, the mechanical movement of the rotary selector spool causes the transmission gear switch to electronically signal the Power Train ECM that the shift is complete. When the output shaft of the transmission is rotating the transmission speed sensor electrically signals the Power Train ECM that the machine has moved. The lower section of the torque converter housing is the torque converter sump. The torque converter sump is the oil sump for power train system. The power train gear pump is located at the rear of the torque converter. This is a two-section gear pump. The rear section is the power train scavenge pump section and the front section is the power train charging pump section. The power train scavenge pump section will pull oil through the magnetic screen. The magnetic screen is located at the bottom of the transmission case. The oil from the bottom of the transmission case is transferred into the torque converter sump. The power train charging pump section pulls oil from the torque converter sump through a suction screen. Oil flows from the power train charging pump section to the power train oil filter. The flow of oil is split after going through the power train oil filter. Some of the oil is sent to the torque converter lockup clutch and solenoid valve. The rest of the oil is sent to the transmission hydraulic control. The oil that is sent to the torque converter lockup clutch and solenoid valve is used to engage the torque converter lockup clutch. When the lockup clutch solenoid is energized by the Power Train ECM, the lockup clutch valve will send oil to the lockup clutch. The lockup clutch is engaged. The machine will be in direct drive. When the lockup clutch solenoid is de-energized the lockup clutch valve will allow the oil in the lockup clutch to drain to the torque converter housing. The lockup clutch will disengage and the machine will be in torque converter drive. The oil that is sent to the transmission hydraulic control also is sent to the upshift solenoid and the downshift solenoid. The basic components of the transmission hydraulic control are the rotary actuator, the selector and pressure control valve, and the pressure control valve. When the upshift solenoid or the downshift solenoid is activated, oil is sent to the rotary actuator. The rotary actuator turns the rotary selector spool in the selector and pressure control valve. This sends oil to the pressure control valve.

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The pressure control valve sends oil at the correct rate so that the correct clutches in the transmission are engaged smoothly. The rotary selector spool can be manually moved through all the positions when the engine is stopped. This is done by removing a plug on the side of the transmission case. The rotary selector spool is in the NEUTRAL position when the spool is turned manually in a clockwise direction to the farthest point. The counterclockwise order of each detent position after the NEUTRAL position is REVERSE, FIRST, SECOND, THIRD, FOURTH, FIFTH, SIXTH, SEVENTH and EIGHTH speed. SEVENTH and EIGHTH speed may not be used. The relief valve in the selector and pressure control valve will control the maximum pressure in the transmission charging system. When the relief valve opens oil is sent past the torque converter inlet relief valve and to the torque converter. If the torque converter inlet oil pressure gets too high, the torque converter inlet relief valve will open. This oil will flow into into the transmission case. The oil that is sent to the torque converter is used as the hydraulic coupling inside the torque converter. The oil exits the torque converter through the torque converter outlet relief valve. The torque converter outlet valve will control the pressure of the oil inside the torque converter in order to keep the torque converter full of oil at all times. The oil flows from the torque converter outlet relief valve to the power train oil cooler. The oil is sent from the power train oil cooler to the transmission for lubrication. The transmission lubrication oil flows through the transfer gears and the transmission. This oil is used for cooling and for lubrication. This oil is then deposited in the transmission case.

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Gear Pump (Power Train)

The pump has two sections: 1. Power train charging pump section 2. Power train scavenge pump section The pump is driven by a gear on the torque converter. Power train charging pump section (1) is located on the drive end of the power train gear pump. This pump section takes oil from the torque converter sump. The oil flows through a suction screen. The oil is then sent to the power train oil filter (3). The oil is then split. Some of the oil is sent to the torque converter lockup clutch and solenoid valve. This oil is used to engage the torque converter lockup clutch. The rest of the oil is sent to the transmission hydraulic control. This oil will be used to engage the proper clutches in the transmission. Some oil will flow from the transmission hydraulic control to the torque converter. This oil will be used as the hydraulic coupling during torque converter drive. Oil that leaves the torque converter is sent to the power train oil cooler. The oil will flow from the power train oil cooler to the transfer gears and to the transmission for lubrication. Power train scavenge pump section (2) takes oil from the transmission case reservoir. The oil flows from the transmission case reservoir through a magnetic screen. The oil flows from the magnetic screen to power train scavenge pump section (2). Oil will flow from power train scavenge pump section (2) to the torque converter sump.

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Magnetic Screen (Transmission)

The magnetic screen is fastened to transmission case reservoir (4). As the oil flows through tube assembly (1), the oil flows through the openings that are between magnets (2). The magnets are installed on the tube assembly so that the same magnetic ends are next to each other. As the oil flows over magnets (2), metal particles are stopped by magnets (2). The oil then flows through screen (3). Other foreign particles are stopped as the oil flows through screen (3). The particles are not allowed to go into the power train system. The oil flows from screen (3) to the power train scavenge pump section of the power train gear pump. The oil is sent back to the torque converter sump.

Construction of the magnetic screen (1) Tube assembly (2) Magnets (3) Screen

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Oil Filter (Power Train)

Power train oil filter (1) is fastened to the left side of the main frame rail behind the front wheel. The oil sampling valve (3) is located on power train oil filter (1). Oil from the power train charging pump section flows to power train oil filter (1) through inlet (2). Power train oil filter (1) has two filter elements. During normal operation, the oil flows through the elements. The oil flows from the elements to outlet (5) and to outlet (6). The oil that flows through outlet (5) is sent to the transmission hydraulic control. This oil is used to engage the proper clutches in the transmission. Some oil will flow from the transmission hydraulic control to the torque converter. This oil will be used as the hydraulic coupling during torque converter drive. Oil that leaves the torque converter is sent to the power train oil cooler. The oil will flow from the power train oil cooler to the transfer gears and to the transmission for lubrication. The oil that flows through outlet (6) is sent to the torque converter lockup clutch and solenoid valve. This oil is used to engage the torque converter lockup clutch. The filter elements stop any debris that is in the oil.

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Transmission Hydraulic Control

Top view of the transmission hydraulic control (1) Upshift solenoid (2) Rotary actuator (3) Pressure control valve (4) Downshift solenoid (5) Selector and pressure control valve (6) Outlet to the torque converter (7) Manifold (8) Inlet from the power train charging pump section (9) Torque converter inlet relief valve (10) Inlet for lubrication system

Front view of the transmission hydraulic control (2) Rotary actuator (3) Pressure control valve (5) Selector and pressure control valve (7) Manifold (9) Torque converter inlet relief valve (11) Manifold

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Operation of components in the Transmission Hydraulic Control Component

Operation (Function)

Upshift solenoid (1)

This solenoid controls the movement of rotary actuator (2) during upshifts.

Rotary actuator (2)

This actuator controls movement of the rotary selector spool in selector and pressure control valve (5).

Pressure control valve (3)

This valve controls oil flow, the rate of pressure increase and of pressure decrease, and oil pressure in the clutches.

Downshift solenoid (4)

This solenoid controls the movement of rotary actuator (2) during downshifts.

Selector and pressure

This valve controls system pressure and the amount and direction of

control valve (5)

pilot pressure oil that is sent to pressure control valve (3).

Manifold (7)

This manifold sends pump oil to rotary actuator (2).

Torque converter inlet

This relief valve controls the pressure of the inlet oil to the torque

relief valve (9)

converter.

Manifold (11)

This manifold sends oil to the clutches.

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Selector and Pressure Control Valve (Transmission)

Selector and pressure control valve in NEUTRAL with a stopped engine (1) Passage (6) Chamber (2) Passage (7) Chamber (3) Priority reduction valve (8) Passage (4) Neutralizer valve (9) Relief valve (5) Rotary selector spool (10) Torque converter inlet relief valve

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(11) Chamber (12) Passage (13) spring assemblies (two) (14) Cam (15) Passage

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Service Training 773D Off highway Truck

Operation of components in the Selector and Pressure Control Valve Valve

Function

Priority Reduction Valve (3)

This valve controls the pressure of the pilot oil that is available to rotary selector spool (7).

Neutralizer valve (4)

When the transmission is not in NEUTRAL and the engine is started, this valve stops the flow of pilot oil to rotary selector spool (7).

Rotary selector spool (5)

This valve sends pilot oil to the pressure control valve. This pilot oil determines the transmission clutches that will be engaged.

Relief valve (9)

This valve controls the maximum pressure in the transmission hydraulic system.

Torque converter inlet

This valve controls the maximum inlet oil pressure to the torque

relief valve (10)

converter.

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Valve Station (Clutch Released)

This schematic shows the positions of the valve station components at the start of modulation before the clutch is fully engaged (primary pressure). Valve movement is initiated when pilot oil from the rotary selector spool moves the selector piston to the left as shown. Movement of the selector piston accomplishes two purposes: 1. The drain passage at the decay orifice is blocked. 2. The load piston springs are compressed.

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Valve Station (Clutch Filling)

Compressing the load piston springs moves the reduction valve spool to the left against the force of the inner spring. This movement opens the supply passage (from the pump) and permits pressure oil to flow to the clutch. As the clutch fills, pressure oil opens the ball check valve and fills the slug chamber at the left end of the reduction valve spool. At the same time, oil flows through the load piston orifice and fills the chamber between the end of the load piston and the selector piston. The load piston orifice provides a pressure drop and time elay in the flow of oil to the load piston chamber. This condition helps control the rate of modulation. Filling the load piston chamber is made possible when the selector piston covers the drain passage at the decay orifice.

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Valve Station (Clutch Released)

The load piston has now moved completely to the left against the stop. The modulation cycle is completed and the clutch pressure is at its maximum setting. Because this is a modulation reduction valve, the maximum pressure setting of the clutch is lower than the system pressure. At the end of the modulation cycle, the pressure in the slug chamber moves the reduction valve a small distance to the right to restrict the flow of supply oil to the clutch. This is the “metering position” of the reduction valve spool. In this positon, the valve maintains precise control of the clutch pressure. During operation, an engaged clutch is designed to leak a relatively small but steady volume of oil. This leakage help prevent high oil temperatures and provides additional lubrication for the planetary gears and bearings. As clutch leakage occurs, the clutch pressure and the pressure of the oil in the slug chamber will start to decrease. At this point the load piston springs move the reduction valve spool a small distance to the left to open the supply passage. Pressure oil from the pump again enters the clutch circuit and replaces the leakage. Then, the clutch pressure in the slug chamber moves the spool back to the right thereby restricting the flow of supply oil to the clutch. This metering action continues during the entire time that the clutch is engaged.

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Transmission Planetary

Components of the transmission (1) Input shaft (2) Coupling hub (3) No. 2 clutch (4) No. 1 clutch (5) Planetary carrier (6) Sun gear (7) Planetary gears (8) Ring gear (9) Ring gear (10) Planetary gears (11) Planetary carrier

(12) Coupling hub (13) Sun gear (14) Planetary carrier (15) Planetary gears (16) Ring gear (17) Planetary gears (18) Planetary carrier and output shaft (19) Planetary gears inner (20) Ring gear (21) Rotating housing (22) Center shaft

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(23) Sun gear (24) No. 3 clutch (25) Rotating housing (26) No. 4 clutch (27) Ring gear (28) No. 5 clutch (29) Sun gear (30) No. 6 clutch (31) Sun gear (32) No. 7 clutch (33) Planetary gear outer

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Service Training 773D Off highway Truck

Transmission Planetary Power from the engine goes to the torque converter. The power then goes through the drive shaft to the transfer gears. The transfer gears are fastened directly to the front of the transmission case. The power then goes through the transmission to the differentia. The transmission has seven forward speeds and one reverse speed. REVERSE and NEUTRAL use only torque converter drive. At lower ground speeds, FIRST speed uses torque converter drive. At higher ground speeds, FIRST speed uses direct drive. As the ground speed increases in FIRST speed, the lockup clutch of the torque converter engages. This provides FIRST speed with direct drive. The speeds SECOND through SEVENTH use direct drive. There is a short period of torque converter drive between the direct drive speeds. This occurs while the clutches engage in the transmission. After the clutches are engaged, the torque converter lockup clutch automatically engages. The torque converter is in direct drive. Torque converter drive during the shifts provides smooth, automatic shifting. The transmission has a combination of two rotating clutches, five stationary clutches, and five planetary units. This provides seven forward speeds and one reverse speed. No. 2 clutch (3) and No. 4 clutch (26) are the rotating clutches. Input torque goes from the transfer gears to input shaft (1). Input shaft (1) drives the transmission input clutch arrangement. NO. 1 clutch (4), NO. 2 clutch (3) and NO. 3 clutch (24) are part of the transmission input clutch arrangement. The remainder of the clutches are in the outputsection of the transmission. Center shaft (22) connects the input section to the output section. Center shaft (22) is splined to planetary carrier (11). Center shaft (22) also carries the sun gears that drive the output section of the transmission. Center shaft (22) and input shaft (1) turn the same direction.

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Engagement of Transmission Clutches

Transmission Speed NEUTRAL

Engaged Clutches in the Transmission 4

REVERSE

1 and 7

FIRST speed

1 and 6

SECOND speed

3 and 6

THIRD speed

2 and 6

FOURTH speed

3 and 5

FIFTH speed

2 and 5

SIXTH speed

3 and 4

SEVENTH speed

2 and 4

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Lubrication of the Transmission

Lubrication of the transmission (1) Input shaft (3) No. 2 Clutch (4) No. 1 Clutch (22) Center shaft (24) No. 3 Clutch (26) No. 4 Clutch (28) No. 5 Clutch(38) Passage

(30) No. 6 Clutch (32) No. 7 Clutch (34) Passage (35) Passage (36) Passage (37) Passage

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(39) Passage (40) Passage (41) Balance piston of No. 2 clutch (42) Passage (43) Balance piston of No. 4 clutch (44) Passage

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Service Training 773D Off highway Truck

Lubrication of the transmission

Oil for the lubrication of the transmission comes from the torque converter. The torque converter outlet relief valve sends oil to the power train oil cooler. The oil flows from the power train oil cooler to the transmission hydraulic control. The oil is split. Some of the oil is used to lubricate the transfer gears. The rest of the oil is used to lubricate the transmission. The transmission lubrication oil goes to a manifold. The distribution manifold divides the oil for the transmission. Some of the oil from the distribution manifold goes through passage (34) for lubrication of the input section of the transmission. The rest of the oil goes into passage (36) for lubrication of the output section of the transmission. The oil in passage (34) goes through passage (35) for lubrication of No. 1 carrier. Oil for the balance piston (41) comes from passage (39). This oil then goes to passage (42) for lubrication of No. 1 clutch (4) and for lubrication of No. 2 clutch (3). The oil in passage (36) goes to several different locations. The oil will go through drilled passages to No. 3 clutch (24) and to balance piston (43). The oil also goes through drilled passages to center shaft (22). The oil goes around the outside of center shaft (22) in order to provide lubrication of the bearings of No. 4 clutch (26) and of the carriers. Oil flows from passage (38) to passage (40) for lubrication of the outer planetary gears. Oil also goes into passage (37) of center shaft (22). This oil is for lubrication of the bearings for input shaft (1), for lubrication of the bearings for center shaft (22) and for lubrication of No. 2 carrier. Oil from passage (36) also goes into passage (44). This oil provides lubrication for No. 5 clutch (28), for No. 6 clutch (30) and for No. 7 clutch (32).

Operation of the Balance Pistons in the Rotating Clutches

The oil that flows to balance piston (41) of the No. 2 clutch and to balance piston (43) of the No. 4 clutch is used to balance the centrifugal force of the oil. The centrifugal force of the oil is caused by the rotation of the No. 2 clutch and the No. 4 clutch. The centrifugal force of the oil that is behind the clutch piston in the rotating clutches causes a small amount of clutch engagement in the rotating clutch. The centrifugal force of theoil that is behind the balance piston balances the centrifugal force of the oil that is on the clutch piston.

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General Information Warning

Sudden movement of the machine or release of air or oil under pressure can cause possible injury or death to persons on or near the machine. To prevent possible injury or death, do the procedure that follows before testing and adjusting the Hydraulic System. 1. Move the machine to a smooth horizontal location. Move away from any machines that are working and any personnel. 2. Move the transmission control to the NEUTRAL position. Fully raise the dump body of the truck. 3. Activate the parking brakes. Stop the engine. 4. Permit only one operator on the machine. Either keep other personnel away from the machine or keep other personnel in the sight of the operator. 5. Place blocks in front of the wheels and behind the wheels. 6. Install the retaining pin for the dump body. 7. Make sure that the transmission rotary selector spool is in the NEUTRAL position. 8. Make sure that all air pressure and oil pressure is released before any fittings, hoses or components are worked on. 9. Push on the brake pedal many times until there is no brake air pressure. Visual Checks are the first steps for troubleshooting a problem. The visual checks will determine the problems that can be corrected quickly.

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Visual Inspection (Power Train) Perform a Visual inspection at the beginning of troubleshooting a problem. Perform the inspection while the engine is turned off. Put the transmission control in the NEUTRAL position and put the transmission rotary selector spool in the NEUTRAL position. Engage the parking brake.

Check the oil level

Inspect the oil level in the torque converter sump. Note: Many problems in the power train are caused by low oil levels or by air in the oil. If the engine has not been started for several minutes, this oil level check will ensure that oil is in the transmission and that the engine can be started. If the machine has not been overnight or an extended period of time and the engine has not been started, the oil level will be high. An accurate oil level check can be performed after the oil is hot.

Warning

Do not check for leaks with your hands. Pin hole (very small) leaks can result in a high velocity oil stream that will be invisible close to the hose. This oil can penetrate the skin and cause personal injury. Use cardboard or paper to locate pin hole leaks. Inspect all oil lines, hoses and connections for damage or for leaks. Look for oil on the gound under the machine. Note: If oil can leak out of a fitting or a connection, air can leak into the system. Air in the system can be as bad as a low amount of oil.

Check the electrical system

Inspect the fuse for the Power Train Electronic Control Module, the harnesses and the electrical connectors. Refer to the proper Electrical Schematic. With the engine start switch and the battery disconnect switch in the OFF position, check the 10 ampere fuse for the Power Train Electronic Control Module. If the fuse is open, replace the fuse. Inspect the electrical harnesses for damaged wires or for broken wires. Disconnect each connector and look for pins and sockets that have been bent, broken or removed. Look for any foreign material inside the connectors. The connectors must be tightened with normal force. The connectors must be disconnected with the same amount of force.

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Check the Power Train Electronic Control Module. For procedures, refer to Power Train Electronic Control System, SENR2668.

Check the batteries

Check the batteries. Turn the battery disconnect switch ON.

Check the filters and the screens

Inspect the power train oil filter, the transmission magnetic screen and the suction screen. Note: The power train oil filter has a bypass valve. A bypass valve allows oil to bypass the oil filter elements whenever the difference in pressure between the inlet oil and the outlet oil in the oil filter is too high. Any oil that does not go through the filter elements goes directly in the hydraulic circuit. Dirty oil causes restrictions in the valve orifices, the sticking valves, etc. If any contamination is found in the filter elements or the screens, all the components of the transmission hydraulic system must be cleaned. Do not use any damaged parts. Any damaged parts must be removed and new parts must be installed.

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Specifications (Power Train) Shift points at nominal engine speed

Upshift

Engine Speed

1C to 1L 1L to 2

1540 6 40 2170 6 30

Transmission Output Speed 323 455

2 to 3

2150 630

630

3 to 4

2150 630

853

4 to 5

2150 630

1145

5 to 6

2150 630

1549

6 to 7

2150 630

2089

Downshift

Engine Speed

7 to 6

1500 6 30

Transmission Output Speed 1972

6 to 5

1500 6 30

1458

5 to 4

1500 6 30

1081

4 to 3

1500 6 30

799

3 to 2

1500 6 30

595

2 to 1L

1415 6 30

415

1L to 1C

1400 6 30

293

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Specifications for the Torque Converter Outlet Relief Valve .

Pressure setting for the outlet relief valve ............. 414 6 34 kPa (60 6 5 psi) Torque converter outlet pressure at stall speed ........... 414 6 34 kPa (60 6 5 psi) Torque converter stall speed at operating temperature ...................... 1832 rpm

Spacer chart for the Outlet Relief Valve

Pt. No. for the Spacers

Thickness of the Spacers

Change in Pressure as a Result of One Spacer

5M-9624 Spacer

0.25 mm (0.01 inch)

5 kPa (0.73 psi)

5M-9623 Spacer

0.90 mm (0.035 inch)

18 kPa (2.61 psi)

5M-9622 Spacer

1.60 mm (0.063 inch)

31 kPa (4.50 psi)

Power Train Oil Filter

Pressure setting for the bypass valve ............. 276 6 28 kPa (40.0 6 4.0 psi)

Lockup Clutch and Solenoid Valve

Pressure Reduction Valve Pilot pressure at low idle .............................. 1725 6 70 kPa (250 6 10 psi)

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Chart Of Shims For The Pressure Reduction Valve Pt. No. for Thickness of Change in Primary Pressure the Shims the Shims as a Result of One Shim 5J-2721 Shim

0.13 mm (0.005 inch)

10 kPa (1.5 psi)

6J-3993 Shim

0.25 mm (0.01 inch)

19 kPa (2.8 psi)

5J-1036 Shim

0.80 mm (0.031 inch)

60 kPa (8.7 psi)

Modulation Reduction Valve Pressure at low idle ...................................... 1720 6 70 kPa (249 610 psi) Lockup clutch primary pressure at low idle ....... 960 6 35 kPa (139 6 5 psi)

Chart Of Shims For The Modulation Reduction Valve (1) Pt. No. for Thickness of Change in Primary Pressure the Shims the Shims as a Result of One Shim 8J-4452 Shim

0.12 mm

10 kPa (1.4 psi) (0.005 inch)

2S-0675 Spacer

0.40 mm

32 kPa (4.6 psi) (0.016 inch)

9J-1330 Shim

0.79 mm

62 kPa (9.0 psi) (0.031 inch)

(1)

Before an adjustment is performed, be certain that the valve springs are not weak or broken.

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Transmission Pressure Control Valve Station

(1)

Engaged Clutch

A

B

C

E

F

G

H

2

1

7

5

4

6

3

Type of Test Clutch Pressure At High Idle

Pressure 2265 6 115 2940 6 165 2940 6 165 2250 6 125 2240 6 125 2940 6 165 2480 6 140 kPa (3296 kPa (426 6 kPa (426 6 kPa (326 6 kPa (325 6 kPa (426 6 kPa (360 6 17 psi) 24 psi) 24 psi) 18 psi) 18 psi) 24 psi) 20 psi)

Primary Clutch Pressure At Low Idle

440 6 315 6 315 6 310 6 300 6 315 6 330 6 20 kPa 20 kPa 20 kPa 20 kPa 20 kPa 20 kPa 20 kPa (64 6 3 psi) (46 6 3 psi) (46 6 3 psi) (45 6 3 psi) (44 6 3 psi) (466 3 psi) (48 6 3 psi)

(1)

Station “D” is not used

Shims For The Pressure Control Valve Pressure Change Per Shim Station(1)

A

B

Engaged clutch

Thickness of Shim

2 Pressure Change

1 Pressure Change

0.13 mm (0.005 inch)

14 kPa (2.0 psi)

20 kPa (2.9 psi)

E

7 5 Pressure Pressure Change Change 5J-2721 Shim 20 kPa 15 kPa (2.9 psi) (2.2 psi)

0.25 mm (0.010 inch)

28 kPa (4.1 psi)

41 kPa (5.9 psi)

0.41 mm (0.016 inch)

45 kPa (6.5 psi)

65 kPa (9.4 psi)

6J-3993 Shim 41 kPa 30 kPa (5.9 psi) (4.4 psi) 4M-1751 Spacer 65 kPa 48 kPa (9.4 psi) (7.0 psi)

125 kPa (18.2 psi)

5J-1036 Shim 125 kPa 92 kPa (18.2 psi) (13.3 psi)

0.80 mm (0.031 inch) (1)

C

87 kPa (12.6 psi)

Station “D” is not used. 40

F

G

H

4 Pressure Change

6 Pressure Change

3 Pressure Change

15 kPa (2.2 psi)

20 kPa (2.9 psi)

17 kPa (2.5 psi)

30 kPa (4.4 psi)

41 kPa (5.9 psi)

33 kPa (4.8 psi)

48 kPa (7.0 psi)

65 kPa (9.4 psi)

53 kPa (7.7 psi)

92 kPa (13.3 psi)

125 kPa (18.2 psi)

103 kPa (14.9 psi)

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Transmission Hydraulic Control Clutch Pressure - Test

Tools Needed Qty 6V-3079 Pressure Hose Assembly 6V-4143 Coupler Assembly 14 (1) 6V-6064 Transmission Test Cover 1 8T-0855 Pressure Gauges (4000 kPa (580 psi)) 7 9S-1721 Extension (1/4 inch square drive) 1 9U-6635 Reversible Ratchet 1 (1) FT1874 Transmission Test Cover 1 (1) Only one type of transmission test cover is necessary. Note: An 8T-5200 Signal Generator/Counter can be used to shift the transmission during the diagnostic tests instead of manual shifting. Note: Make sure that the filters and the screens are clean before you test any pressures. Make sure that the oil is at operating temperature before you perform this test. This test will determine if the following conditions exist: l The transmission clutch pressures are correct. l There is too much oil leakage in a clutch. Warning

Personal injury or death can result from sudden machine movement. Sudden movement of the machine or release of air pressure or oil pressure can cause injury to persons on or near the machine. To help prevent possible injury before testing and adjusting any air system or hydraulic system, perform the procedure in the Testing and Adjusting, “General Information” section.

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Procedure For Manual Shifts Of The Transmission This procedure will save time when the transmission is tested. Shifts can be performed on the transmission instead of using the transmission shift lever in the operator’s station. Notice

To prevent possible damage to the flexible coupling, never manually shift the transmission by rotating the flexible coupling for the transmission switch. 1. Be certain that the transmission shift lever is in the NEUTRAL position.

GML 2. Disconnect the wiring harness from the upshift solenoid, the downshift solenoid and the lockup solenoid. 3. Remove the plug for the rotary selector spool from the left side of the transmission case while the engine is stopped. 4. Use a 9S-1721 Extension (1/4 inch square drive) and a 9U-6635 Reversible Ratchet to turn the transmission rotary selector spool. When the ratchet is fully turned in a clockwise direction, the rotary selector spool is in the NEUTRAL position. The order of the detent positions is NEUTRAL, REVERSE and FIRST speed through SEVENTH speed. Note: There is approximately 30 degreesof rotation between each detent of the rotary selector spool. Note: An 8T-5200 Signal Generator/Counter can be used to shift the transmission during the diagnostic tests instead of manual shifting.

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Procedure

Note: If a FT1874 Transmission Test Cover is used, a gauge can be installed at pressure tap (1) in order to check the pilot pressure. If a 6V-6064 Transmission Test Cover is used, be certain that the plug is installed at pressure tap (1). 1. Disconnect the electrical harness from the lockup clutch solenoid. Note: This will allow testing the clutch pressures in a direct drive situation without removing the drive axles from the machine. 2. Remove the solenoid guard and the large cover from the top of the transmission case. Install the FT1874 Transmission Test Cover in the place of the large cover. Use four bolts to hold the test cover in position.

Top view of the transmission hydraulic control (9) Downshift solenoid valve (10) Upshift solenoid valve (46) Torque converter inlet relief valve (E) Pressure tap for the No. 2 clutch (G) Pressure tap for the charging pressure of the transmission (H) Pressure tap for the No. 1 clutch (I) Pressure tap for the No. 5 clutch (J) Pressure tap for pilot oil of the transmission hydraulic control (K) Pressure tap for the No. 7 clutch (L) Pressure tap for the No. 4 clutch (M) Pressure tap for the No. 6 clutch (O) Pressure tap for the No. 3 clutch (P) Pressure tap for the lubrication system

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3. Connect 8T-0855 Pressure Gauges (4000 kPa (580 psi)) to the nipples at pressure taps (A), (B), (C), (E), (F), (G) and (H). 4. Start the engine. Run the engine at the low idle rpm with the transmission in NEUTRAL. 5. Record the pressures on the gauges. 6. Use a 9S-1721 Extension (1/4 inch square drive) and a 9U-6635 Reversible Rachet. Move the transmission rotary selector spool to the REVERSE position. Note: An 8T-5200 Signal Generator/Counter can be used to shift the transmission during the diagnostic tests instead of manual shifting. 7. Record the pressures on the gauges. 8. Manually shift the transmission into all of the forward speeds. Record the pressures on the gauges during each shift. 9. Increase the engine rpm to the high idle rpm while the transmission is in the SEVENTH speed. 10. Record the pressures on the gauges. 11. Decreases the engine rpm to the low idle rpm. Manually shift the transmission to the SIXTH speed. Increase the engine rpm to the high idle rpm. Record the pressures on the gauges. 12. Repeat Step 11 in all the speeds including REVERSE and NEUTRAL. Be certain that the engine rpm is decreased before each downshift is per formed. 13. Stop the engine with the transmission rotary selector spool in NEUTRAL. 14. Compare the actual clutch pressures that were recorded with the pressures that are provided in Table 41. 15. After the pressures are recorded, remove the test equipment. Note: There is no adjustment for these clutch pressures. Refer to Testing and Adjusting, “Transmission Hydraulic Control Primary Clutch Pressure - Test and Adjust” for the adjustments for the primary pressure.

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Hydraulic Lines - Truck Body Hoist Hydraulic System

Hoist Conrol Valve Hold

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Hoist Conrol Valve Raise

Hoist Conrol Valve Float

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Truck Body Hydraulic system The truck body hydraulic system consists 1. Hydraulic tank 2. Hoist brake gear pump 3. Hoist control 4. Hoist control position sensor 5. Body up down switch 6. Output from the power train ECM to proportioning solenoids 7. Hydraulic control valve 8. Hoist cylinders. The Hydraulic Tank

It supplies oil to the Hoist & brake gear pump and to the parking brake release section of the secondary steering & brake pump. It has screens at the suction port to the hoist & gear pump and brake cooling oil return port. Oil returns to tank from Brake cooling system, hoist control valve and towing diverter valve. It has drain ports for the secondary brake control valve, lip seal case of the parking brake valve, brake make up tank. It has an air breather and two sight gauges for checking oil levels during hoist lowered & raised conditions.

Hoist & Brake gear pump

This is a two section pump supplying oil to 1. Hoist control valve 2. Parking brake release, rear brake cooling system & pilot oil to hoist proportioning solenoids.

The hoist control

This is located at the left of the operator seat and has four positions Raise, Hold, Float and Lower. The machine should normally be operated with the hoist in float position.

Hoist control position sensor

This is a pulse width modulated position sensor and sends duty cycle signals to the power train ECM. The power train ECM processes and energizes the proportioning solenoids for moving the hydraulic control valve spool. The signal for the hoist control position sensor is also used to neutralize the transmission if the hoist control position is in reverse position.

The body up & down

This is located on a bracket on the rear of the frame. The magnet assembly is connected to the dump body. The switch assembly is used to limit the top gear while the dump body is up. The signal is also used to control the snub position while the dump body is lowered. The signal from this is also used to provide warnings to the operator when the truck is moving with the dump body up.

The hydraulic control valve

This consists of 1. Pilot oil lines from the brake pump section 2. Supply line from the hoist pump section 3. Pilot operated and spring centered direction control spool 4. Proportioning solenoids to move the actuators 5. High pressure & low pressure relief valves 6. Three delivery lines leading to hoist rod end, base end & rear brake cooling system 7. Drain lines from the actuators, cooling relief line, high & low pressure relief lines 8. Hoist system relief lines having a dump spool & stem assembly.

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The hydraulic control valve in hold condition

In the hydraulic control valve in the hold condition does not receive current from the power train ECM to either of the proportioning solenoids. Hence the pilot oil is blocked by the actuators and the centering springs hold the control valve spool in the hold condition. In this condition, the inlet pump oil flows to the rear brake cooling system through one of its delivery lines. The brake cooling relief valve relieves excess oil and returns to the hydraulic tank through the return line.

The hydraulic control valve in raise condition

In the raise condition, the raise proportioning solenoid receives 1.9 Amps current. Pilot oil in the actuator is allowed to drain. Pilot oil in the other side actuator pushes the direction spool to the left which allows the pump oil to flow through the head end line to the hoist cylinder. Oil in the rod end of the cylinder is allowed to go the hoist cylinder. Orifices in the cylinder will control the rate of oil that leaves the rod end of the hoist to control the speed of the raise of the hoist. This can happen when a load shifts during the dump. Some of the oil is also sent as signal oil to the stem. This shifts the stem so that a low pressure relief valve is blocked and the pump oil flowing through the dump spool to flow to the high pressure relief valve. If the pressure opens the valve, the dump spool will shift upward and the pump oil is sent to the tank.

The hydraulic control valve in lower condition

In the lower condition of the hoist control the proportioning solenoid for the lower position receives a current of 1.9 Amps and pulls the actuator so that the pilot oil is drained. The spool moves to the right by the other side pilot oil. In this condition pump oil flows to the rod end line to the hoist cylinders. Base end oil of the hoist is sent to the tank through the control valve, in this condition no signal pressure is sent to the stem and hence pump oil can flow to the low pressure relief valve. If the low pressure relief valve opens the spool will shift upward and the pump is sent to the hydraulic tank.

The hydraulic control valve in float condition

In the float condition, the respective solenoid receives 1.69 Amps of current from the power train ECM. Pilot oil in that side of that actuator is given the passage to drain. The pilot oil in the other side of the spool pushes the direction spool to the right. As only small amount of pilot oil is drained the control valve spool does not move all the way to the lower position. The pump oil flow divides in both the hoist rod end line and brake oil cooling line.

In Snub condition

In this snub position, the proportioning solenoid receives only 0.810Amps current. The pilot oil that is draining is restricted and hence the direction spool will move to the left. This restricts the oil flow from the head end of the cylinder and lowers the speed of the dump body. The pump oil flows to the rod end and to the rear brake cooling system. Oil in the head end of the hoist is drained to the tank through the control valve.

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The hoist cylinders

The hoist cylinders raise the dump body in two stages. The pump oil flows through a tube in the rod assembly to the head end of the hoist cylinders. The pressure of the pump oil moves the outer cylinder and the body connected to it. While the cylinder is moving up, the oil in the chamber between the inner and the outer cylinder flows into the outer cylinder chamber through the grooves in the inner tube. When the cylinder end cap portion moves all along the inner cylinder tube is also pushed up by the oil pressure in the head end of the outer cylinder. While the inner cylinder is moved up the oil in the chamber between the inner cylinder and the rod assembly flows through the orifices into the tube of the rod assembly and from there to the control valve. The inner cylinder is pushed up until the tube end cap contacts the piston which is bolted to the top of the rod assembly. The orifices control the travel speed of the actuator at the end of the second stage. When the hoist are lowered on the truck frame by keeping the lever in the lower or float positions the pump oil flows through the openings in the rod assembly through the orifices into the chamber between the rod and the inner cylinder tube. The oil pushes the cylinder tube downwards as the chamber is filled with oil until the inner tube is fully retracted. Further lowering occurs due to the weight of the dump body. When the body gets to the specified position the flow that is leaving the cylinder is restricted due the snub position and the dump body moves at a very reduced speed, the body sits on the frame.

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Cylinder Drift Note: Perform this test with an empty dump body and hydraulic oil above 38°C (100°F). 1. Move the hoist control to the RAISE position. 2. When the first stage of the hoist cylinders is extended by 305 mm (12 inch), move the hoist control to the HOLD position. 3. The dump body wiil push the cylinder head of the first stage by 6.35 mm (0.250 inch) onto the second stage of the hoist cylinders. Use a stopwatch and record the required time. The acceptable time for cylinder drift is relative to the temperature of the hydraulic oil in the hoist cylinders. See Table for the acceptable time.

Acceptable Cylinder Drift

Minutes 7.0

Oil Temperature 38° to 48°C (100° to 119°F) 49° to 64°C (120° to 149°F) 65 °C (150°F)

4.1 3.0

Cylinder Drift 6.35 mm (0.250 inch) 6.35 mm (0.250 inch) 6.35 mm (0.250 inch)

Excessive cylinder drift can be caused by the following conditions: l Leaks in the lines between the hydraulic oil tank and the hoist cylinders. l Worn control valve spool. l Worn seals in the hoist cylinders.

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Steering System

Hydraulic Schematic

The steering system in addition to the mechanical linkages has 1. Suspension struts 2. Steering spindle 3. Tie rod arms 4. Bell crank 5. Tie rod assemblies contains hydraulic system to move the steering boosters.

Steering hydraulic system

The steering hydraulic system consists 1. Steering hydraulic tank 2. Flow & pressure compensated axial piston pump 3. Steering check & relief valve 4. Steering metering pump 5. Steering cylinder check & relief valves 6. Secondary steering & brake release electric drive pump 7. Secondary steering solenoid valve 8. Load sensing line connecting steering metering pump, piston pump and the secondary steering solenoid valve 9. Pressure reducing valve 10. Steering pump oil pressure switch 11. Steering cylinders.

Pump

The pump is a pressure compensated variable displacement axial piston pump. When the steering wheel is turned and the cylinders need oil the steering pump sends pressurized oil through load sensing line to pressure and flow compensatory valve. Due to this, the oil in the actuator piston is drained and the pump is at the maximum stroke. If the pressure of the steering system reaches

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the pressure setting of the high pressure cut off valve, the pressurized oil flows to the actuator piston and acts against the bias piston spring force. This creates a minimum, swash plate angle to destroke the pump to low pressure stand by condition. Now the pump output is equal to the pressure setting of the high pressure cut off valve.

No steer position

In the no steer position, the load sensing line from the steering pump is at low pressure. Due to the low signal pressure to the flow and pressure compensatory valve, the pump oil flows to the actuator piston and creates a minimum swash plate angle to destroke the pump to a low pressure standby condition. This output needs the requirements of lubrication and normal leakages in the piston pump. The leakage oil flows to the steering hydraulic tank through a screen assembly.

Steering check & pressure valve

The steering check & pressure valve acts as a manifold for the steering system. Pressurized oil from the primary and the secondary steering systems has check valves before both the above pump deliveries enter this valve. It has backup relief valves for both primary and secondary steering systems separately. These relief valves protect both the primary and secondary steering systems if the high pressure cut off valve in the primary system or secondary system mail relief valve fails. The pressurized oil from the piston pump also flows to the pressure reducing valve in this check & relief valve. The pump oil flows from this valve to the steering metering pump. Also, the return oil from the steering metering pump flow to the steering hydraulic tank. The pressure reducing valve protects the steering pressure switch from damages during high pressures.

Steering metering pump

The steering metering pump has a metering section and a control section. Oil from the pump goes into the control section when the steering wheel is turned control section sends oil to the metering section. Metered oil again flows into the control section and from there either through left or right end ports the oil goes to the steering cylinders. The return oil from tne steering cylinders flows to the steering check & relief valve for returning to the tank. In the no steer condition there is no alignment between the holes and the sleeve and the slots in the spool. The small amount of flow (Thermal Bleed) in the centered position which is normal keeps the metering pump full of oil. This will give a quick response time to the steering demands. This also helps the oil in the metering pump warmed up during cold weather operations. As the steering

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wheel is turned faster there is an increase in the flow the metered oil causing the steering cylinder piston rods move with increased speed. When the steering wheel is not turned, centering springs brings the spool and the sleeve to the neutral condition. The steering metering pump has a load sensing port. The load sensing port is connected to the inlet of the metering pump through an orifice. Oil pressure in the inlet is felt in the load sensing line. This signal pressure is communicated through the flow & pressure compensatory valve and to the secondary steering solenoid valve.

Steering cylinder check & relief valves

Steering cylinder check & relief valves located in the steering metering pump prevents the damage from high pressure oil in the steering circuit when the steering wheel is stationary and the outside force an a wheel moves the steering cylinder rod into or out of the cylinder by allowing the oil flow to the low pressure side of the cylinders.

Pressure switch

Pressure switch monitors the output of the piston pump. The alarm will sound and the action light and the secondary steering alert indicator will flash until the steering pressure reaches the deactuation pressure. If the system pressure drops to the actuation pressure the alarm should sound and the action light should flash. If the system pressure is below the deactuation pressure the power train ECM will energize the secondary steering relay behind the cab and then energize a second larger relay located on the frame near the suspension cylinder. This relay will activate the secondary steering and brake release electric drive pump. If the alarm sounds and the alert indicator is flashing this is an indication of primary steering oil flow. Note: A warning light is displayed only if the ground speed is above 8 Km/hr.

Secondary steering parking brake release pump

Secondary steering parking brake release pump when activated the power train ECM will de-energize the secondary steering solenoid valve. Load sensing signal pressure oil from the steering metering pump will flow through the solenoid valve to the load sensing valve and the load sensing valve spool is moved. The load sensing valve controls the flow of oil from the secondary steering and brake release electric drive pump to steering check & relief valve.

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Primary Steering Operation The steering system is a closed centre system. Oil from the piston pump flows through the primary steering check valve to the steering metering pump. When the steering wheel is turned the metering pump sends fixed amount of oil to the steering cylinders. The speed of the turn is decided by the rate of steering wheel rotation. The steering linkage is designed in order to use the head end of each cylinder as a mechanical stop. Return oil from the steering boosters flows through the steering metering pump, steering check & relief valve to the tank through the filter.

Secondary Steering Operation Oil from the secondary steering pump flows through the secondary steering check valve and flows to the primary steering check valve. But the oil flow behind the check valve (This pressurized oil does not open the primary steering check valve). The secondary steering main relief valve is located in the load sensing valve of the secondary steering and brake release electric drive pump behind the plug. This controls the maximum pressure in the steering system. Oil flow after the oil passes through the primary steering check valve is similar to the primary steering operation.

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Brake System - Air Control Components

(16) Front brake air control valve (17) Front brake air ratio valve (18) Air system pressure protection valve (19) Service brake air control valve (20) Air suspension seat (21) Remove these lines when the Automatic Retarder Control (ARC) is installed. Also remove this pressure switch. (22) Air horn solenoid (23) Retarder air control valve (24) Secondary brake air control valve (25) Parking brake air control valve (26) Secondary brake inverter valve (27) Automatic Retarder Control (ARC) valve (attachment) (28) Secondary air tank (29) Cab wall

(1) (2) (3) (4) (5) (6) (7) (8) (9)

Air tank check valve Air relief valve for primary air tanks Primary air tanks Drain valve Front brake inverter valve Brake air relay valve for the front brakes Brake air relay valve for the rear brakes Brake air system pressure protection valve Brake air relay valve for the Automatic Retarder Control (ARC) (10) Air compressor with an air compressor governor (11) Air dryers with air relief valves (12) Parking and secondary brake valve (13) Brake master cylinder (front) (14) Brake master cylinder (rear) (15) Air horn

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(A) This is the brake cylinder overstroke limit switch (overstroke switch). The overstroke switch is normally closed. The overstroke switch opens when the pistons in the master cylinder travel too far. A brake overstroke condition can result from low brake fluid level, air in the brake hydraulic circuit, leakage in the brake hydraulic lines, and master cylinder piston seal leaks. An indicator will come on in the cab and the alarm will sound. Do not operate the machine until the cause for the overstroke has been corrected. (B) This is the secondary brake and parking brake pressure switch. This pressure switch is normally open. The pressure switch is closed by air pressure when the parking brakes or secondary brakes are released. When this pressure switch is open, this pressure switch signals the Power Train Electronic Control Module (Power Train ECM) to allow rapid shifts. (C) This is the brake air pressure sensor. The brake air pressure sensor monitors brake air pressure. The operator will be alerted to a condition of low air pressure. (D) This is the manual retarder pressure switch. This pressure switch is normally open. This pressure switch is closed when the retarder air control valve is applied. This switch operates the indicator in the cab. (E) This is the service brake and retarder pressure switch. This pressure switch is normally closed. This pressure switch is opened by air pressure when the service brakes, the retarder, or the Automatic Retarder Control (ARC) are applied. When this pressure switch is open, the pressure switch signals the Power Train ECM in order to allow the transmission to perform rapid shifts. The Power Train ECM also indicates that higher engine rpm is needed for upshifts or for downshifts of the transmission when this pressure switch is open. (F) This is the stop lights pressure switch. This pressure switch is normally open. This pressure switch is closed by air pressure when the service brakes, the retarder, or the Automatic Retarder Control (ARC) are applied. When this pressure switch is closed, this pressure switch activates the stop lights. (G) This is the Automatic Retarder Control pressure switch. This pressure switch is normally closed. This pressure switch is opened by air pressure in order to indicate that the Automatic Retarder Control (ARC) is operating. The pressure switch verifies that air pressure is being provided through the Automatic Retarder Control valve. (H) Standard air lines. (I) Air lines for the Automatic Retarder Control (ARC) valve (27) (attachment)

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Brake System - Component Description The brake system can be divided into 2 major groups. Brake air system and brake hydraulic system. The components of the air system are 1. Air Compressor 2. Compressor Governor 3. Air Drier 4. Primary Air Tanks 5. Secondary Air Tanks 6. Air System Pressure Protection Valve 7. Brake Air System Pressure Protection Valve 8. Service Brake Air Control Valve 9. Secondary Brake Control Valve 10. Secondary Brake Inverter Valve 11. Front Brake Inverter Valve 12. Front Brake Ratio Valve 13. Brake Air Relay Valve 14. Air /Hydraulic Cylinder (Master Cylinder) 15. Front Brake On/Off Valve 16. Parking Brake Valve 17. Retarder Control Valve 18. Double Check Valves

Air compressor

The air compressor driven by the engine power draws air from the air inlet manifold and supplies to the air reservoirs through the air drier.

Compressor governor

The (compressor) governor operates with compressor unloader pistons to control the air pressure in the system. The cut out pressure setting is 120 6 5 psi and the min cut in pressure is 95 psi.

Air drier

The air drier removes the moisture from the air system and also protects the air system from damages. The air drier relief valve which is set to 175 psi cannot be adjusted.

Primary air tanks

The primary air tanks whose relief pressure is set permanently to 150 psi supplies air to service brakes, automatic lubrication system, air horn and the retarder.

Secondary air tank

The secondary air tank located in the compartment behind the cab supplies air to the secondary brake circuit.

Check valves

Two check valves, one for primary reservoir and one for secondary reservoir to prevent the reverse flow of air from the tanks.

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Pressure protection valves

The two pressure protection valves one of air system located in the compartment behind the cab and the other for brake air system located above the primary tank prevents complete loss of air pressure in the event of failure of either secondary air system or any accessories device and in the event of failure of the relay valve for ARC respectively. Pressure protection valves allow flow of air through them only when the supply pressure reaches the value of the preset spring pressure and closes when the air pressure reaches the value of closing pressure.

Foot operated service brake air control valve

The foot operated service brake air control valve when pushed down closes the exhaust port and modulates the air pressure. Then this air is sent for the primary tank to the brake air reiay valve. When the pedal is released the delivered air is discharged through its exhaust port.

Secondary brake control valve

The secondary brake control valve is red in color and is foot operated. When pushed down its exhaust port is closed and sends the modulated air from the secondary brake tank to the secondary brake invertor valve. When the pedal is released the delivered air is discharged through its exhaust port.

Secondary brake invertor valve

The secondary brake invertor valve is located in the compartment behind the cab. When the secondary brake applied restricts, modulates the air pressure which is sent to the parking and secondary brake valve and front brake invertor valve to control the braking force. When released, air pressure flowing to signal port is blocked by the secondary brake valve and to front brake invertor valve and all the four brakes are released.

Front brake invertor valve

The front brake invertor valve located above the primary tanks, when the secondary brake control is applied this valve modulates front brake invertor valve air to flow to front brake master cylinder. When released full air pressure flows to signal port. Outlet port is connected to exhaust port to discharge the delivered air.

Front brake ratio valve

Front brake ratio valve located at the rear of the cab behind the cover controls the air pressure to front brake relay valve. When the service pedal is partially applied and the supply pressure is below 65 psi this valve allows only 50 % of the air pressure to flow from the outlet port to the relay valve to apply the front brakes partially, if the supply pressure at-least 65 psi the full air pressure flows through the valve. This is for the rear brakes to engage first for the operator to have maximum control of the machine.

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Brake air relay valve

Brake air relay valve when air pressure is available at the signal port the primary air tank air port of the valve is connected to the delivery line to go to the master cylinder.

Air / Hydraulic cylinder

Air / Hydraulic cylinder (Master cylinder) when air is supplied to the air chamber of the cylinder the pressurized air pushes the piston and rod down compressing the spring to close the supply oil passage this moves the power (oil) piston down top send the oil to slack adjustor. In the front the oil pressure is approximately 23 times of the air pressure due to the difference in the areas of oil and air pistons. In the rear the oil pressure is 6.6 times of the air pressure due to the oil and air piston sizes. Note: In the rear master cylinder over stroke indicator switch is provided which actuates when the piston moves beyond 75% of the full travel contacting the over stroke pin for warning purposes through CEMS.

Air control valves

Air control valves for parking and front brake are similar in construction and operation. If the lever is in the on condition the air flows from the inlet to outlet and if the lever is in off condition the inlet (supply) is blocked and the delivered air is exhausted through the exhaust passage of these valves.

Slack adjuster

Slack adjuster ensures constant timing between pushing the service brake pedal and stopping of the machine with new or worn out brakes. Slack adjuster is in the oil system for the rear brakes and is full of oil. A low pressure oil is always available at the outlets of the slack adjuster to the brake group due to the small spring between the small piston and the plate closing the above outlet passage.

Brake group

Rear wheel assembly is splined into the hub assembly in the brake group. Friction discs which have inner teeth are engaged with the teeth of the hub and reaction plates which have external teeth kept adjacent to friction discs are engaged with the fixed ring gear of the anchor group. Service piston and the emergency piston over the service piston are kept under the spring tension. In this condition wheel is in the braked condition pressurized oil in the parking and secondary brake valve when supplied on the parking piston chambers acts against the springs and keeps the brakes in the released condition. The brake group has inlet and outlet lines for the cooling oil circulation. It has oil line for service brake application which acts on the service piston, further it has two sets of ducone seals, one for preventing the leakage of cooling oil externally and the other for preventing of mixing of cooling oil with planetary oil.

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Towing diverter valve

Towing diverter valve located on the side of the hydraulic tank allows oil from the electrically driven pump to parking and secondary brake valve when the spool of the valve is moved to the left. When moved to the right the passage to the above valve is blocked and opens another passage to the hoist hydraulic tank.

Brake oil cooler

Brake oil cooler, the bottom most in the cooler group is located on the right side of the engine. Oil comes to the cooler from the hoist control valve and from the parking and secondary brake valve. Cooled oil from the cooler goes to make up tank for supplying the necessary oil for the brake master cylinders. The excess oil from the make up tank returns to the hoist hydraulic tank. The oil from the cooler also goes to both rear brake groups and after cooling the same returns to the hoist hydraulic tank through a strainer.

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Brake Air Lines When the engine is started air from the compressor flows to the air drier and from there through one way check valve enters the primary tank. When the air pressure in the tanks builds up above the cutting pressure of the pressure protection valve the valve opens and air flows to the front brake inverter valve, service brake air control valve, air horn solenoid, (optional air suspension seat) and to the secondary brake tank. When the air pressure reaches the cut out pressure of the compressor governor air flow to the system is stopped by the governor arrangement. When the air pressure drops below 60 psi the action alarm in the cab will sound. Air pressure flows from the secondary brake tank to the secondary break inverter valve. With secondary brake inverter valve in off position air pressure from secondary tank flows through secondary brake inverter valve to parking brake air control valve. If the parking braking valve is in on position the flow of air to the parking and secondary brake control valve is stopped and due to this the flow of oil is blocked. If the parking brake control valve is in off position the opposite will happen and the spring applied brakes in the brake group are released by the oil pressure.

Service brake application

When the service brake pedal is pushed down air pressure from the primary air tank flows through service brake air control valve to the rear brake air control valve which connects primary tank air line to the rear brake master cylinder. Also this air pressure closes the passage to ARC due to the double check valve

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over the master cylinder. The air pressure also flows to the front brake air control valve and if it is in ON position (air line is blocked there only if the front brake air control valve is in OFF condition) and from there it flows through front brake ratio valve to the front brake relay valve which connects the primary tank line to the front brake master cylinder. When the pedal is released the flow of air through the service brake control valve is blocked and the delivered air to the relay valves is exhausted through the exhaust port of the service brake air control valve and the delivered air to the master cylinders is exhausted through the respective brake air relay valves. Note: If the retarder air control valve is applied the primary tank air which is supplied through the service brake air control flows through double check valve to the rear brake air relay valve. The double check valve over the master cylinder closes the passage to the ARC relay valve and allows the air flow to act on the rear brake master cylinder air piston to apply only the rear brakes. The engine must be kept between 1500 to 1900 rpm to keep the sufficient flow of oil through the brake groups. The braking force is controlled by the position of the retarder brake lever. When the reatrder lever is moved to the released position the flow through this valve is blocked and the delivered air is exhausted through this retarder valve. Do not increase the speed while the retarder is on.

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Emergency brake application

Air pressure from secondary air tank flows to the secondary brake air control valve and secondary brake inverter valve. When the pedal for secondary brake air control valve is partially depressed to the ON position, a portion of the full supply pressure is sent to the control passage of secondary brake inverter valve. The secondary brake inverter valve will block some of the air pressure that is flowing to parking and secondary brake valve and to the signal passage of front brake inverter valve. The result is modulated secondary braking action. When the pedal on secondary brake air control valve is held in the full ON position, air pressure from secondary air tank flows through the secondary brake air control valve to the control passage of secondary brake inverter valve. The secondary brake inverter valve blocks all of the air pressure that was flowing to the parking and secondary brake valve as a result the oil pressure to the brake housing will also be blocked and the springs will apply the parking brake. When the pedal on the secondary brake air control valve is held in the full ON position, the secondary brake inverter valve also block all of the air pressure that was flowing signal passage of front brake inverter valve. When the air flow to the signal passage is blocked, full air flow is allowed to flow through the front brake inverter valve. The air flow then passes through a double check valve at the front brake master cylinder. The pressurized oil flows to the caliper brake assembly to apply the front brakes.

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Schematic for the Rear Parking Brake

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Hydraulic Lines - Brake and Hoist

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When you release the pedal for the secondary brake air control valve, the pedal is returned by a spring to the OFF position and the air is not sent to the control passage of the secondary brake inverter valve. Due to this air pressure from the secondary air tank flows to parking and secondary brake valve and to front brake inverter valve. This air flow will cause parking and secondary brake valve to send oil to the brake housing. The oil pressure will release parking brakes for the rear wheels. The air flow to front brake inverter valve blocks the air that is flowing to the master cylinder for hydraulic caliper service brakes for the front wheels. As a result the hydraulic caliper for the front wheels will be released.

Front wheel brakes

The front wheel brakes of are of caliper disc type. A plate assembly fastened to the axle is used the support the caliper assembly. Front wheel supported on the axle by two taper roller bearings is bolted with a disc. Brake carrier linings of the caliper assembly on each side of the disc are used for braking the front wheels. The hydraulic oil from the front brake master cylinder flows into the passage of the caliper which connects all the piston bores. Pressurized oil forces the pistons against brake caliper linings causing friction to slow the rotation of the disc and the front wheels. Continued application of the brakes stops the rotation of the wheel.

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Service Brake Application

When the service or retarder brake is applied oil pressure from the master cylinder is sent through slack adjuster to the service & retarder brake oil chamber of the brake group. As the oil pressure increases, the service & retarder piston pushes the friction discs and steel plates together and the friction between them causes the rotation of the wheel to slow down. A continued application of the above brakes stops the rotation of the wheel assembly. When the above brakes are released, the return springs will push back the service & retarder piston and in turn the piston pushes the oil back into the slack adjuster. The cooling oil which flows through the brake group cools the discs & plates and returns the hydraulic tank.

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Parking brake application

In the normal condition when parking brakes are not applied i.e., the parking & secondary brake valve is not supplied with air pressure, the parking & secondary brake springs push on the parking & secondary brake piston against the service & retarder brake piston. As a result the friction discs and the steel reaction plates are held together and hence the connected hub and the rear wheel which is splined to the hub are stopped from rotation. When the parking & secondary brake valve is supplied with air pressure, pressurized oil from the brake section of the hoist & brake pump section is sent to the Parking & secondary brake release oil chamber of the brake group through the Parking & secondary brake valve. The oil pressure pushes the Parking & secondary brake piston and spring & guide along with service & retarder piston away from the friction discs & steel plates separating them from contacting each other and there by releasing the spring applied brakes.

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Gauges, Switches and Warnings

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Warning Operation WARNING OPERATION

Warning Category

1

Warning Indications 1 Alert Action Action Indicator Lamp Flashes 3 Flashes 4 Sounds 4

1

X

2

X

X

3

X

X

X

Required Operator Action

Possible Result 2

No immediate action required. The system needs attention soon.

No harmful or damaging effects.

Change machine operation or perform maintenance to the system.

Severe damage to components.

Immediately perform a safe engine Operator injury or severe damage shutdown. to components.

The warning indications which are active, are marked with an X.

The Caterpillar Monitoring System notifies the operator of an immediate or impending problem with a machine system. Warning operation begins when the main display module receives a problem signal that reflects an abnormal machine condition or the main display module detects a control system problem. Switches, sensors and other electronic control modules on the machine provide signals to the main display module. l FLASHING of the alert indicator (approximately nine times per second). l FLASHING of the action lamp (ON one second, OFF two seconds). l SOUNDING of the action alarm (ON one second, OFF two seconds).

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Approved Lubricants HINDUSTAN 773D-I & 773D-II SERIES DUMPERS Application

Change Period (Hours) Under Normal Conditions

Capacity in Liters (Approx.)

Lubricant Specifications

Engine Crankcase

250

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SAE 15W 40

Trarsmission / Torque converter

53 1000

C4 SAE 30

Hoist and Brake Tank

133

Steering Tank

34 1000

SAE 10 W

Ride cylinders - Front & Rear Differential and Final drives

50 2000

140 SAE 50

Front Wheel Bearing (Both LH & RH)

500

8

Coolant conditioner

System Drained

6

HPL - INTAC Liquid (Refer Engine Manual)

As Required

NLGI NO.2 OR MPGM

Grease points Rod brgs.* Rear suspension cyl. brgs.* Body pivot brgs.* Front suspension cyl. brgs.* Fan drive brg and belt tightener.° Steering cyl. brgs.° Steering tie rod and pin brgs.° Hoist control bellcrank.° Driveshaft U.J and spline.° Hoist cyl. brgs.° Rear axle housing ‘A’ frame brg.°

*50 °250

The Lubricants must meet the requirements of API CG4 grade at the minimum. The CH4 are the preferred grade of lubricants 71

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Compartment Interval

Recommended Oil Change Interval

Recommended Sampling

Sampling Valve

Engine Transmission and Torque Converter Steering

250 Hours 1000 Hours

250 Hours 500 Hours

Yes Yes

1000 Hours

500Hours

Yes

Hoist and Brake

1000 Hours

500 Hours

Yes

Differential and Final Drive Front Wheel

2000 Hours

500 Hours

No

500 Hours

500 Hours

No

Sampling the compartments at every 250 hours provides information about the condition of the oil. This information can be used to determine the performance of a particular oil. Also, data from frequent sampling enables close monitoring of component wear rates.

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Maintenance Interval Schedule When Required

Air Conditioner Filter - Clean Brake Oil Cooler Screen - Clean Cab Air Filter - Clean/Replace Circuit Breakers - Reset Engine Air Filter Primary Element - Clean/Replace Engine Air Filter Secondary Element - Replace Engine Air Precleaner - Clean Ether Starting Aid Cylinder - Replace Frame and Body - Inspect Fuses - Replace Hoist and Brake Tank Suction Screen - Inspect/Clean/Replace Oil Filter - Inspect Torque Converter Sump Screen - Clean Traction Control System (TCS) - Test Window - Clean Window Washer Bottle - Fill Window Wiper- Inspect Replace

Every 10 Service Hours or Daily

Air Tank Moisture and Sediment - Drain Backup Alarm - Test Brakes, Indicators and Gauges - Test Cooling System Level - Check Engine Oil Level - Check Fuel System Water Separator- Drain Fuel Tank Water and Sediment - Drain Hoist and Brake Tank Oil Level - Check Seat Belt - Inspect Secondary Steering - Test Steering System Oil Level - Check Torque Converter Sump Oil Level - Check Walk-Around Inspection

Initial 50 Service Hours

Parking Brake Release Oil Filter - Replace Power Train Oil Filter - Replace Steering System Oil Filter - Replace

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Every 50 Service Hours or Weekly

Body Pivot Bearings - Lubricate Front Suspension Cylinder Rods - Lubricate Hoist Cylinder Bearings - Lubricate Rear Axle A-Frame Bearing - Lubricate Rear Axle Housing Lateral Control Rod Bearings - Lubricate Rear Suspension Cylinder Bearings - Lubricate Steering Cylinder Bearings - Lubricate Steering Tie Rod and Pin Bearings - Lubricate

Every 2000 Service Hours or 1 Year

Cooling System Coolant Sample - Obtain Differential Thrust Pin Clearance - Check Differential and Final Drive Breather - Replace Differential and Final Drive Oil - Change

Every 6000 Service Hours or 4 Years

Cooling System Coolant (ELC) - Change Cooling System Relief Valve - Clean Cooling System Water Temperature Regulator - Replace Engine Water Pump - Inspect

Initial 250 Service Hours (or at first oil change)

Engine Valve Lash and Bridge - Check Engine Valve Rotators - Inspect Frame and Body Support Pads - Clean / lnspect

Every 250 Service Hours or Monthly

Air Conditioner - Test Air Conditioner Filter - Clean Air Dryer - Check Belts - Inspect / Adjust / Replace Battery - Recycle Battery Electrolyte Level - Check Battery, Battery Cable or Battery Disconnect Switch - Replace Braking System - Test Cab Air Filter - Clean / Replace Cooling System Coolant Additive (DEAC) - Add Differential and Final Drive Oil Level - Check Drive Shaft Slip Joint - Lubricate Engine Oil and Filter - Change Engine Oil Sample - Obtain Fan Drive Bearing and Belt Adjusting Pulley - Lubricate Front Wheel Oil - Inspect Front Wheel Oil Level - Check Master Cylinder Breather - Clean

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Magnetic Plug (Differential) - Check Magnetic Plug (Wheels) - Check Tire Inflation - Check Initial 500 Service Hours

Cooling System Coolant Sample - Obtain

Every 500 Service Hours or 3 Months

Differential and Final Drive Oil - Inspect Engine Crankcase Breather - Clean Frame - Clean/lnspect Front Wheel Oil - Change Fuel System - Prime Fuel System Primary Filter - Clean / Replace Fuel System Secondary Filter - Replace Fuel Tank Cap and Strainer - Clean Hoist and Brake Tank Breather - Replace Obtain S.O.S Samples Parking Brake Release Oil Filter - Replace Power Train Oil Filter - Replace Steering System Oil Filter - Replace Suspension Cylinder - Check Torque Converter Sump Breather - Clean Transmission Magnetic Screen - Clean

Every 1000 Service Hours or 6 Months

Air Dryer Desiccant - Replace Frame and Body Support Pads - Clean/lnspect Hoist and Brake Tank Oil - Change Rollover Protective Structure (ROPS) - Inspect

Every 3000 Service Hours or 2 Years

Cooling System Coolant (DEAC) - Change Cooling System Coolant Extender (ELC) - Add Cooling System Pressure Cap - Clean/Replace Engine Valve Lash and Bridge - Check Engine Valve Rotators - Inspect Radiator Core - Clean

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Maintenance Procedure Rear Wheel Bearing Adjust

(1) Spindle (2) Shims (3) Retainer Plate (4) Bolts

View A-A (3) Retainer Plate (4) Bolts

Note: Before performing this adjustment, you will need to release the brakes. In order to release the parking brake, remove the purge valve from opening (A). This opening is marked with a “P”. Then, connect a manual hydraulic pump or an electric hydraulic pump to opening (A). Continue to operate the pump until the brake is fully released. To learn more about releasing the brakes, refer to the information about towing that is located in the Air System and Brakes Systems Operation and Testing And Adjusting. Notice

If it becomes necessary to use an outside hydraulic source to release the parking brake do not exceed the relief pressure of the parking and secondary brake control valve. Exceeding the relief pressure can dam age seals and other parts in the circuit.

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Adjustment Procedure 1. Thoroughly, clean all of the tapped holes in the end of spindle (1). 2. Install retainer plate (3) with five new bolts (4) to spindle (1). Install bolts (4) so that each bolt is equally spaced around retainer plate (3). Note: Do not use any shims (2) at this time. 3. Tighten bolts (4) to a torque of 140 N.m (103 lb ft). Turn the wheel for two complete revolutions. 4. Tighten bolts (4) to 140 N.m (103 lb ft). Turn the wheel for two complete revolutions. 5. Loosen bolts (4) by 120 degrees. Turn the wheel for two complete revolutions. 6. Tighten bolts (4) to a torque of 70 6 5 N.m (52 6 4 lb ft). Turn the wheel for two complete revolutions. 7. Repeat Step 6 until no further movement of bolts (4) occurs. 8. Use a depth micrometer to determine the distance from the outside face of retainer plate (3) to the end of spindle (1). Measure the depth of the two holes that are opposite to each other on retainer plate (3). Calculate an average depth from these two measurements. 9. Use an outside micrometer to determine the thickness of retainer plate (3) at the bolt holes. Measure the thickness of retainer plate (3) at the same locations that were used in Step 8. Calculate an average thickness from these two measurements. 10. Find the gap between the end of spindle (1) and the inside face of retainer plate (3). To find this gap, subtract the dimension that was found in Step 9 from the dimension that was found in Step 8. 11. Calculate the shim pack thickness. Add 0.230 + 0.000 - 0.050 mm (0.009 + 0.000 - 0.002 inch) to the distance that was found in Step 10.

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12. Assemble shim pack (2) so that the shim pack thickness is the value that was found in Step 11. Remove bolts (4) and retainer plate (3). 13. Install shim pack (2). 14. Install retainer plate (3) over shim pack (2). Install ten new bolts (4). 15. Evenly torque opposite bolts (4) to 250 6 15 N.m (185 6 10 lb ft). 16. Repeat Step 15 until no further movement of bolts (4) occurs.

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Fault Codes & ET Component Identifiers (CID) 1 for Caterpillar Monitoring System (MID030) 2 CID No. Component 0096 Level Sender (Fuel) 0177 Temperature Sensor 0248 Data Link 0263 Sensor Power Supply 0271 Alarm 0324 Lamp (Action) 0601 Pressure Sensor (Brake Air) 0819 Display Data Link 0821 Display Power Supply 0830 Temperature Sensor (Brake Oil) 1 2

The CID is a diagnostic code that indicates which component is faulty. The MID is a diagnostic code that indicates which electronic control module diagnosed the fault.

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Component Identifiers (CID) 1 for

the XMSN/Chassis ECM (MID027)2 CID No. 0168 0190 0248 0269 0420 0444 0562 0590 0627 0700 0701 0702 0704 0706 0707 0708 0709 0724 0725 0773 0967 1236 1362 1394 1 2

Component System Voltage Eng Speed Sensor Signal Data Link Sensor Power Supply Relay (Secondary Steering) Start Relay Caterpillar Monitoring System Eng Electronic Control Module Parking Brake Press Switch Transmission Gear Sensor Speed Sensor (Transmission Output) Transmission Position Sensor Pressure Switch (Service Brake) Electronic Control (Body Up Switch) Solenoid Valve (Upshift) Solenoid Valve (Downshift) Solenoid Valve (Lockup Clutch) Solenoid Valve (Body Raise) Solenoid Valve (Body Lower) Rotary Position Sensor Machine Application Body Up Indicator Lamp Location Code Solenoid Valve (Exhaust Diverter)

The CID is a diagnostic code that indicates which component is faulty. The MID is a diagnostic code that indicates which electronic control module diagnosed the fault.

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FMI No. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 1

Failure Mode Identifiers (FMI) 1 Failure Description Data valid but above normal operational range Data valid but below normal operational range Data erratic, intermittent or incorrect Voltage above normal or shorted high Voltage below normal or shorted low Current below normal or open circuit Current above normal or grounded circuit Mechanical system not responding properly Abnormal frequency, pulse width or period Abnormal update Abnormal rate of change Failure mode not identifiable Bad device or component Out of calibration. Parameter failures Parameter failures Parameter not available Module not responding Sensor supply fault Condition not met Parameter failures

The FMI is a diagnostic code that indicates what type of failure has occurred.

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Component Identifiers (CID) 1 for the Engine Control (MID036) 2 CID No. 0001 0002 0003 0004 0005 0006 0007 0008 0009 0010 0011 0012 0042 0091 0100 0101 0110 0164 0168 0174 0175 0190 0248 0253 0254 0261 0262 0263 0267 0268 0273 0274 0275 0291 0338 0544 0545 1 2

Component Cylinder 1 Cylinder 2 Cylinder 3 Cylinder 4 Cylinder 5 Cylinder 6 Cylinder 7 Cylinder 8 Cylinder 9 Cylinder 10 Cylinder 11 Cylinder 12 Injection Actuation Pressure Control Valve Throttle Sensor Output Oil Pressure Signal Crankcase Pressure Signal Coolant Temperature Injection Actuation Pressure Signal Battery Voltage Fuel Temperature Signal Oil Temp Signal Engine RPM Signal CAT Data Link Personality Module Mismatch ECM Timing Calibration Analog Sensor Supply Digital Sensor Supply Shutdown Inputs System Parameters Turbocharger Outlet Pressure Atmospheric Pressure Right Turbocharger inlet Pressure Engine Cooling Fan Solenoid Prelube Pump Relay Engine Fan Speed Sensor Signal Start Aid Relay

The CID is a diagnostic code that indicates which component is faulty. The MID is a diagnostic code that indicates which electronic control module diagnosed the fault. 82

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Using Caterpillar Electronic Technician (ET) to Determine Diagnostic Codes

Connections for the Electronic Technician (ET) The components that are needed to use CAT ET to determine diagnostic codes are shown below. (1) (2) (3) (4) (5)

IBM-compatable personal computer with Caterpillar Electronic Technician software. 139-4166 Data Link Cable or 7X-1570 Data Link Cable. 7X-1425 Cable and 4C-6805 Adapter. Caterpillar Electronic Technician software. 7X-1700 Communication Adapter Tool.

Note: Caterpillar Electronic Technician (ET) is a software program that can be used on an IBM compatible personal computer. Reference: In order to use ET, order the Special Publication, JERD2124, “ET Single Use Program License”, Special Publication, JEHP1026, “Information and Requirements Sheet”, Special Publication, JERD2129, “ET Engine and Machine Data Subscript”, Special Publication, JEBD3003, “ET Software Getting Started Book”, and Special Publication, JERD2142, “Data Subscription”. The Special Publication, JEHP1026, “Information and Requirements Sheet” lists the required hardware and the features of ET. The ET service tool is not necessary to determine the diagnostic codes but the tool makes the tasks easier and faster. The ET service tool can display information on the history of the diagnostic codes and the status of other parameters. These features make the ET service tool useful for troubleshooting.

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The ET service tool connects to the machine service connector in order to communicate with the ECMs over the data link. The service connector is located behind the operator’s seat in the cab. For more information and the locations of the connectors, see Testing and Adjusting, “Electrical Components and Connector Locations” and the Electrical System Schematic in your machine’s Service Manual. Connect the ET to the machine. Turn the key start switch to the RUN position. Start the ET. The ET will initiate communications with the electronic control modules on the machine. The ET will list the available electronic control modules on the machine after communication has been established. Choose the menu item “Transmission”. Use the ET in order to determine the diagnostic codes. Follow the troubleshooting procedures that correspond to the diagnostic codes. See Troubleshooting Procedures.

Location of the Power Train Electronic Control Module The Power Train ECM receives current through a fuse on the fuse block. This current is used to activate the upshift solenoid, the downshift solenoid and the lockup clutch solenoid. These solenoids control the option of converter drive or the option of direct drive. These solenoids also control the direction and the speed. The Power Train ECM also controls the electrical system for the hoist. The Cat Data Link is used to share information with other systems such as the Brake Electronic Control Module (Brake ECM), the Engine Electronic Control Module (Engine ECM), and the Caterpillar Monitoring System. Signals that are sent to the Engine ECM result in reduced engine speed during upshifts and

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Front Suspension Cylinder Charging Procedure Oil Charge Warning

Read all warning labels on the suspension cylinders before servicing. Do not check the oil in the suspension cylinder until all the nitrogen pres sure has been released. Do not, under any condition, remove valves, cover or plugs from the cylinder unless the rod is fully retracted and all the nitrogen pressure is released. Do not stand under the truck when testing or adjusting the suspension cylinders. Sudden movement, up or down, can cause the clearance above your head to change rapidly. Before servicing the suspension cylinders, the truck must be empty and on level ground. Check for and eliminate leakage at all possible locations. Both suspension cylinders must be charged at the same time. If only one cylinder needs servicing, perform the servicing procedure on both cylinders. 1. Put the open end of the suspension charging lines into an approved container. Connect the charging lines to the suspension cylinder charging valves. Turn the charging chuck T-handle clockwise to open the charging valves and allow the oil and nitrogen to drain into the container. 2. After the cylinders have bottomed, leave the charging valves open for approximately five minutes to allow the pressure in the cylinders to equalize. 3. After the pressure has equalized, close the charging valves by turning the charging chuck T-handle counterclockwise. Disconnect the charging lines from the cylinders. 4. Position a thin strip of sheet metal (banding strap) on both suspension cylinders. Place a piece of masking tape on the sheet metal strips with the top edge of the tape even with the top of the spindle. Put a line across the tape below the top edge of the tape. (This line will be used for the oil charge.) 5. Connect the charging lines to the oil charging pump. Put the end of the suspension charging hoses with the charging chuck into an approved container. Cycle some oil through the charging lines to fill them with clean oil.

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Note: Use SAE 10W service classification CC or CD oil for the cylinder oil charging procedure. In remote locations, if an oil charge pump is not available, it is possible to use the hoist system to charge the suspension cylinders with oil. Install a tap in the LOWER port of the hoist system and connect the charging lines to the tap. With the engine at LOW IDLE, carefully move the hoist lever to the LOWER position to inject oil into the cylinders. Follow the oil charging procedure the same as if the oil charging pump was being used. 6. Connect the charging lines to the charging valves and turn the charging chuck T-handle clockwise to open the charging valves. Inject oil into the cylinders until each cylinder extends to the line made on the masking tape. Reference Line For The Oil Charging Procedure................25.4 mm (1.00 inch) Height Of The FT1680 Gauge Block (1) ...........................170.0 mm (6.69 inch) 7. Turn the charging chuck T-handle counterclockwise to close the charging valves and disconnect the charging lines from the oil charging pump. Note: If one cylinder reaches the oil charge line on the tape before the other cylinder, close the gate valve to that cylinder. Continue injecting oil into the other cylinder until it reaches the oil charge line on the tape.

Nitrogen Charge

1. If the temperature outside is more than 11°C (20°F) different from the shop temperature, calculate the amount of shims required under the gauge block. 2. Connect the charging lines to a dry nitrogen cylinder. To prevent oil flow from the suspension cylinders, adjust the nitrogen cylinder regulated pressure to 4150 kPa (600 psi), and open the gate valves. 3. Turn the charging chuck T-handle clockwise to open the charging valves. Raise the suspension cylinders with nitrogen until the gauge blocks (and shims if required) can be installed between the spindle and the cylinder housing. (See the chart for the correct gauge block dimensions.)

Notice

To protect the front cylinder wiper seals from damage when the gauge blocks are installed, make sure the chamfer on the blocks is positioned toward the seals.

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4. Drain nitrogen from the suspension cylinders until the cylinder housings rest on the gauge blocks and the regulated nitrogen pressure is less than 2070 kPa (300 psi). 5. Adjust the regulator on the nitrogen supply to: Initial Pressure Setting For The Nitrogen charging Procedure......4150 kPa (600 psi) Final Pressure Setting For The Nitrogen charging Procedure......2400 kPa (350 psi) 2300 kPa (330 psi) for the 793B 6. Open the charging valves and let the nitrogen flow into both cylinders. Leave the valves open for approximately five minutes to allow the pressure in both front suspension cylinders to equalize. 7. Close the charging valves and the gate valves and shut off the nitrogen pressure at the nitrogen supply tanks. Remove the Nitrogen Charging Group. Install the charging valve caps and torque to 3 to 5 N.m (30 to 45 lb. in.). 8. To remove the gauge blocks, raise the truck body and steer the front wheels from side to side. The suspension cylinders should raise so the blocks can be removed. 9. After the suspension cylinders are properly charged, operate the truck for several load cycles. Then, measure and record the exposed chrome length of both front suspension cylinders and measure and record the amount of chrome that was wiped clean by the wiper seals. These measured dimensions should then be used as a reference whenever inspecting the front suspension cylinder charge condition.

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Front Suspension Cylinder Charging Procedure Reference Line For The Oil Charging Procedure................25.4 mm (1.00 inch) Reference Line For The Nitrogen Charging Procedure(1)... 24.0 mm (4.90 inch) Reference Line For The Nitrogen Charging Procedure(1)..137.0 mm (5.40 inch) Nitrogen Charge

1. Connect the charging lines to a dry nitrogen cylinder, To prevent oil flow from the suspension cylinders, adjust the nitrogen cylinder regulated pressure to: Pressure Setting For The Nitrogen Charging Procedure.......2400 kPa (350 psi) Then, open the gate valves. 2. Turn the charging chuck T-handle clockwise to open the charging valves. Raise the suspension cylinders with nitrogen until the top of the suspension cylinder housing is within the two nitrogen charge lines made in Step 6 of the oil charge procedure. 3. When both suspension cylinders are within the nitrogen charge lines, shut off the nitrogen pressure at the supply tanks. Leave the charging valves and the gate valves open for approximately five minutes to allow the pressure in both rear suspension cylinders to equalize. Note: If one cylinder is within the nitrogen charge lines before the other cylinder, close the gate valve to the cylinder that is within the nitrogen charge lines. Continue charging nitrogen until the other cylinder reaches the same extension. 4. Close the charging valves and the gate valves. Remove the Nitrogen Charging Group. Install the charging valve caps and torque to 3 to 5 N.m (30 to 45 lb. in.). 5. After the suspension is properly charged, operate the truck for several load cycles. Then, measure and record the dimension between the center line of the top mounting pin and the top of the cylinder head of both rear suspension cylinders. Also, measure and record the amount of chrome that was wiped clean by the wiper seals. These measured dimensions should be used as a reference whenever inspecting the rear suspension cylinder charge condition.

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Electronic Control (Body Down or Up Switch) - Adjust

View A (1) Magnet Assembly (2) Body Down or Up switch electronic control (3) Bracket

Note: Before making adjustments to body down or up switch electronic control (2), the pad assembly and the shims must be installed and the dump body must be in the DOWN position. Refer to the Hydraulic System Systems Operation/ Testing and Adjusting, “Pad Assembly (Dump Body) - lnstall and Adjust” for the proper installation of the pad assemblies. 1. Adjust bracket (3) in order to get the correct distance (X) between magnet assembly (1) and body down or up switch electronic control (2). Distance (X) should be 4.0 6 1.0 mm (0.16 6 0.04 inch). 2. Raise the dump body 360 mm (14 inch) above the frame. 3. Use blocking to support the dump body. 4. Adjust body down or up switch (2) until the second light on top of the switch illuminates. Note: The second light is yellow. 5. Remove the blocking. 6. Lower the dump body onto the frame.

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Pad Assembly (Dump Body) Install and Adjust

Proper installation of the body support pads will effectively balance the load weight. This will reduce the risk of possible damage to the chassis. If the body support pads indicate uneven wear, readjusting the shims may correct the problem. Also, if the paint on the frame indicates uneven wear, readjusting the shims may correct the problem.

Procedure To Install Pad Assemblies To The Main Frame

View B (1) Pad assembly (2) Shim

Note: The truck should be on a level surface. The pivot pin for the truck body should be installed. The hoist cylinders should be installed. 1. Mark the location of pad assemblies (1) on the frame rail using the center mounting block on the dump body as a guide. 2. Raise the dump body and install the proper safety device in order to secure the dump body in the RAISE position. Stack one pad assembly (1) and one shim (2) at each location for a pad assembly (1) on the frame rail.

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3. Remove the safety device and lower the dump body. Locate any gaps and add shims (2) in order to close the gaps. 4. Raise the dump body and install the proper safety device in order to secure the dump body in the RAISE position. Bolt pad assemblies (1) and the shim packs to the dump body. Remove the safety device and lower the dump body.

Procedure To Install Pad Assemblies To The Top Of The Main Crossbeam

View A-A (1) Pad assembly (2) Shim (3) Shoe

Note: The truck should be on a level surface. The pivot pin for the truck body should be installed. The hoist cylinders should be installed. 1. Place a pad assembly (1) on each shoe (3) at the front of the dump body. Install as many shims (2) as possible between pad assembly (1) and shoe (3). Remove pad assembly (1) and the shim pack. Add one shim (2) to each shim pack. 2. Raise the dump body and install the proper safety device in order to secure the dump body in the RAISE position. Bolt pad assemblies (1) and the shim packs to shoes (3). Remove the safety device and lower the dump body. No gaps should be visible between pad assemblies (1) and the dump body.

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Relief Valve (Hoist Dual Stage) - Test and Adjust Tools Needed 6v-3079 Pressure Hose Assembly 6v - 4143 Coupler Assembly 8T-0856 Pressure Gauge (6000 kPa (870 psi)) 8T-0860 Pressure Gauge (40000 kPa (5800 psi))

Qty 1 2 1 1

Note: Make sure that the filters and the screens are clean before you test any pressures. Make sure that the oil is at operating temperature before you per form this test. Note: Before you perform any tests, visually inspect the entire hydraulic system for oil leaks and for damaged components. 1. Lower the dump body. Stop the engine. 2. Connect a hose assembly with an 8T-0860 Pressure Gauge (0 to 40000 kPa (0 to 5800 psi)) to pressure taps (5). 3. Start the engine. Operate the dump body repeatedly until the temperature of the hydraulic oil is above 38°C (100°F). 4. Run the engine at high idle and move the hoist control to the RAISE position. 5. After the dump body is fully raised, look at the gauge and hold the hoist control in the RAISE position. The high pressure gauge reading is the relief valve pressure setting of high pressure relief valve (1). The correct pressure setting is 17225 to 17745 kPa (2500 to 2575 psi).

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6. Loosen nut (6). Turn retainer (7) in order to adjust the setting of high pres sure relief valve (1). 7. When high pressure relief valve (1) is correctly set, tighten nut (6).

Relief Valve Test (Low Pressure)

1. Lower the dump body. Stop the engine. 2. Connect a hose assembly with an 8T-0856 Pressure Gauge (0 to 6000 kPa (0 to 870 psi)) to pressure tap (8). 3. Start the engine. Operate the dump body repeatedly until the temperature of the hydraulic oil is above 38°C (100°F).

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4. Lower the dump body onto the truck frame. Note: The body down or up switch must be in the RAISE position before low pressure relief valve (2) can be measured. If the body down and up switch is in the LOWER position the Power Train Electronic Control Module will keep the hoist control valve in the SNUB position. Low pressure relief valve (2) cannot be measured in this condition. 5. Move a magnet in front of the body down or up switch until the alert indicator on the dash turns on. 6. Run the engine at high idle and move the hoist control to the LOWER position. 7. Look at the gauge and hold the hoist control in the LOWER position. The high pressure gauge reading is the relief valve pressure setting. The correct p ressure setting is 3450 6 350 kPa (500 6 51 psi). 8. Loosen nut (10). Turn retainer (9) in order to adjust the setting of low pressure relief valve (2). 9. When low pressure relief valve (2) is correctly set, tighten nut (10).

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Front Wheel - Align

Steetring linkage (1) (2) (B) (F)

Procedure to adjust the front wheel alignment

Clamps on left side tie bar Clamps on right side tie bar Distance between the front tires at the back Distance between the front tires at the front

Use the following Procedure to adjust the front wheel alignment: 1. Raise the axles until the strut rods in the suspension cylinders are fully extended. 2. Move the wheels to a straight ahead position. 3. Measure the distance between the front wheels at location (F). 4. Mark location (F) at each tire. Rotate the tires by 180 degrees. 5. Measure the distance at location (B) between the same marks. 6. Use Table to determine the correct toe-out when the front wheels are off the ground. Correct Toe Out B = F - 58.7 mm (2.31 inch) 7. If the difference that was found in the previous step is not correct, adjust each link assembly by the same number of turns.

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Note: After the adjustment has been made, the tie rods must be of equal length. 8. When the Toe-Out measurement is correct, tighten clamps (1) and (2) to 183 N.m (135 lb ft) and lower the front of the truck. Note: The front wheel toe-in will be correct if the difference between distance (F) and distance (B) is properly adjusted. Also, the suspension cylinders must be properly charged and the suspension cylinders must be at the normal operating range.

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Steering System Operation Checks

The front wheels must be on a dry, smooth hard surface and the hydraulic oil in the steering system must be warm. Start the machine. In first gear, slowly drive the machine while you turn the steering wheel. Drive the machine until the hydraulic oil temperature is approximately 38°C (100°F). Test the steering system with the engine at high idle. Rotate the steering wheel. Measure the time that is required to turn the front wheels from the full right turn position to the full left turn position and back to the full right turn position. If the time is more than 6.0 seconds, there could be a problem in the steering hydraulic system. If the time is less than 5.0 seconds, there could be a problem in the steering hydraulic system. Failures in the steering system can be at least one of the following items: l Broken oil line or a leak in an oil line connection l Worn steering piston pump l Pressure setting of the flow compensator valve in the pressure and flow compensator valve l Pressure setting of the high pressure cutoff valve in the pressure and flow compensator valve l Low pressure setting of the primary steering backup relief valve l Open secondary steering check valve l Worn steering metering pump

Performance Checks

Performance checks of the steering system can be used for the following purposes: l Diagnosis of poor performance l Source of oil leakage inside the hydraulic system

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Duo-Cone Seals - Install Installation Procedure

Note: This procedure is only for Duo-Cone conventional seals. This procedure does not pertain to Duo-Cone floating seals. It is extremely important to follow the correct procedure for installing DuoCone seals. Many seal failures are the direct result of mistakes during installation of the seal components. Note: To aid in assembling the Duo-Cone seals, a 169-0503 Installation Kit (Duo-Cone Seal) is available. The installation kit contains wipes, seal cleaner and seal lubricant.

(1) Toric ring. (2) Seal ring. (3) Housing retaining lip. (4) Housing ramp. (5) Seal ring housing.

(6) Seal ring face. (7) Seal ring ramp. (8) Installation tool. (9) Seal ring retaining lip.

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Warning

Use caution when you are using isopropyl alcohol. Avoid prolonged skin contact with isopropyl alcohol. Vapours may be harmful if inhaled. Use only in a well ventilated area. Do not smoke while using isopropyl alcohol. Isopropyl alcohol is flammable. Do not use near an open flame or near welding operations. Keep isopropyl alcohol away from heated surfaces exceeding 482°C (900°F). 1. Remove any oily film, dust or other foreign matter from all of the seal components. Use isopropyl alcohol and a clean cloth that is free of lint or a paper towel to clean the components Note: All components should be complete!y dry prior to proceeding. Do not allow Oil to contact toric ring (1), housing ramp (4) or seal ring ramp (7) before both seal rings (2) are assembled in Step 11.

2. Position toric ring (1) on seal ring (2). Make sure that toric ring (1) is at the bottom of seal ring ramp (7) and against seal ring retaining lip (9). Note: Make sure that toric ring (1) is straight on seal ring (2). There must not be a twist in toric ring (1). Handle toric ring (1) carefully. Nicks, cuts and scratches can cause leaks.

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3. Position installation tool (8) on seal ring (2) with toric ring (1). 4. Lightly dampen the lower half of toric ring (1) with isopropyl alcohol. Techniques that can be used to dampen toric ring (1) include wiping with a clean cloth that is free of lint. Toric ring (1) can also be dipped into a container with towels or with a foam mat that is saturated with isopropyl alcohol. Note: Do not use Stanisol or any other liquid that evaporates slowly. Do not use a liquid that leaves an oily film

5. Make sure that the lower half ot toric nng (1) is still wet. Use Installation tool (8) to posttion seal ring (2) and toric ring (1) squarely against seal ring housing (5) and under housing retaining lip (3) of seal ring housing (5), as shown.

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6. Measure dimension (A) from seal ring face (6) to the top surface of seal ring housing (5). Check dimension (A) in at least four places (90 degree intervals). The measurements must not differ by more than 1 mm (0.04 inch). Note: If small adjustments are necessary, do not push seal ring (2) directly and do not pull seal ring (2) directly. Use installation tool (8). 7. Toric ring (1) can twist if the toric ring is not completely wet during installation. Burrs on housing retaining lip (3) or on seal ring housing (5) can also cause a twist. Notice

Misalignments, twists and bulges of the toric ring will cause Duo-Cone seal failures. If any of these occur, perform the assembly process over from the beginning. 8. Toric ring (1) must never slip on housing ramp (4) or seal ring ramp (7). To prevent slippage, allow adequate time for evaporation to occur before you proceed with the assembly process Toric ring (1) must roll only on seal ring ramps (7) and on housing ramps (4).

9. Use a clean cloth that is free of lint or a paper towel to wipe off seal ring faces (6). Note: No particles of any kind can be left on the sealing surfaces. A small piece from a paper towel can cause a leak by keeping the sealing surfaces from contacting each other.

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10. Apply a thin film of clean oil on seal ring faces (6) of seal ring (2). Use an appilcator, a disposable tissue or a clean finger to distribute the oil evenly. Ensure that no oil contacts the toric rings.

Notice

Do not slam the seal rings together. High impact can scratch or break the seal components. When all of the seal components are properly aligned, secure all parts tightly. 11. Make sure that both seal ring housings (5) are correctly aligned and con centric. Slowly move the seals toward each other.

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Brake System Air - Purge Tools Needed 6V-4055 Pressure Hose Assembly 6V-4143 Coupler Assembly

Qty 1 2

There are purge valves for the hydraulic brakes on each wheel. Before you use the purge valves to remove air from the oil in the system, the makeup oil tank for the hydraulic brakes must be full. Also, the air system pressure must be more than 550 kPa (80 psi).

Warning

Personal injury or death can result from air in the oil for the brake hydraulic system. Air in the system can prevent complete brake application and it is possible that the wheels on the machine can not be stopped. Air must not be in the oil for the brake hydraulic system to function properly.

Warning

Personal injury or death can result from machine movement. Place blocks in front of and behind the wheels to make sure the machine does not move while the parking brakes are disengaged.

Notice

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, “Caterpillar Tools and Shop Products Guide”, for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose of all fluids according to local regulations and mandates. Note: Purge only one wheel at a time.

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Service Brakes and Retarder Rear Brakes

1. Use a 6V-4055 Pressure Hose Assembly and two 6V-4143 Coupler Assemblies to construct a jumper hose. 2. Apply the parking brake. This will release the pressure in the lines.

(1) Pressure tap on the rear slack adjuster (2) Pressure tap for parking brake release pressure

3. Put one end of the jumper hose on pressure tap (1). 4. Put the other end of the jumper hose on a pressure tap (2).

(P) Purge valve for the parking brake (S) Purge valve for the service brake

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Note: Identification letters are embossed on the purge valves at the top of the brake housing. The purge valve for the parking brake is labelled with a “P”. The purge valve for the service brake is labelled with an “S”. 5. Connect a drain hose from the “S” port to the hydraulic tank or to a suitable container. 6. Run the engine at low idle. Move the parking brake lever to the OFF position. 7. Pull down the retarder control. 8. Open the purge valve “S” on a rear wheel brake housing and purge the brake system. Leave the purge valve open until there is a constant flow of oil. 9. Close the purge valve. Repeat Step 8 for the other rear wheel brake. 10. Close the purge valve. Move the retarder control to the OFF position. Activate the parking brake in order to release the pressure. Remove the jumper hose. Note: In order to verify that all of the air was removed from the service brake lines for the rear brakes, perform the following steps. Note: In order to make sure that the makeup oil tank is full, operate the engine at high idle for 20 seconds before each brake application. 11. Move the parking brake lever to the OFF position in order to allow full travel of the service brake piston. 12. Push down on the brake pedal or pull down the retarder control. 13. Open the purge valve “S” on a rear wheel brake housing and purge the brake system. 14. Repeat Steps 12 through 13 until there is a continuous flow of oil. 15. Close the purge valve. Release the brake pedal or move the retarder control to the OFF position.

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16. Do Steps 12 through 15 on the other rear brake. Note: After you purge the brakes, you may need to reset the actuating pins for the overstroke switch. The actuating pins for the overstroke switch are on the master cylinders. A brake overstroke condition is a Level III warning. When you need to reset the actuating pin, you will push the actuating pin into the housing. Push the actuating pin into the housing until the bottom of the pin is flush with the bottom of the housing.

Front Brakes

Note: In order to make sure that the makeup oil tank is full, operate the engine at high idle for 20 seconds before each brake application. 1. Move the parking brake lever to the OFF position in order to allow full travel of the service brake piston. 2. Push down on the brake pedal or pull down the retarder control. 3. Open the purge valve (3) on a front wheel brake housing and purge the brake system. 4. Repeat Steps 2 through 3 until there is a continuous flow of oil. 5. Close the purge valve. Release the brake pedal or move the retarder control to the OFF position. 6. Do Steps 2 through 5 on the other front wheel brake. Note: After you purge the brakes, you may need to reset the actuating pins for the overstroke switch. The actuating pins for the overstroke switch are on the master cylinders. A brake overstroke condition is a Level III warning. When you need to reset the actuating pin, you will push the actuating pin into the housing. Push the actuating pin into the housing until the bottom of the pin is flush with the bottom of the housing.

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Parking Brake

Though the parking brake application is mechanic it is very important to remove the air from the parking brake release system. 1. Connect a drain hose from the “P” port to the hydraulic tank or to a suitable container. 2. While the engine is operating, move the lever for the parking brake to the OFF position. 3. Open the purge valve “P” on a rear wheel brake housing. Close the purge valve when there is a constant flow of oil. 4. Repeat this procedure for the other rear wheel brake housings.

Front Wheel Bearing Adjustment

Note: Hand tap or wire brush the threaded holes to remove thread lock material prior to doing Step 1. Note: If the wheel assembly has 5P-9118 Self Locking Bolts (5), DO NOT use them for the bearing preload.

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Use 0S-1625 Bolts to set the bearing preload. Also use the 0S-1625 Bolts for final assembly. 1. Install wheel and bearings on axle. 2. Install retainer (4) with three bolts (5) equally spaced (no shims). 3. Tighten bolts (5) to a torque of 100 N.m (74 lb ft) and rotate the wheel. 4. Tighten bolts (5) again to a torque of 140 N.m (103 lb ft) and rotate the wheel. 5. Release the torque from bolts (5) and tighten to a torque of 70 N.m (52 lb ft). Rotate the wheel. 6. Tighten bolts (5) again to a torque of 70 N.m (52 lb ft) and rotate the wheel. 7. To find distance from end of spindle to cone face, measure the distance through the two holes with threads in retainer (4). Find the average of the two measurements. 8. Remove bolts (5) and retainer (4). Measure the thickness of retainer (4) near the holes with threads. Find the average of these measurements. 9. The DIFFERENCE between the average measurements in Steps 7 and 8 PLUS 0.279 mm (.0110 in) is the correct thickness of shims (3) to use. Note: Apply 9S-3263 Thread Lock to bolts (5) before assembly. 10. Install the correct thickness of shims (3), retainer (4) and bolts (5). While the wheel is turned, tighten bolts (5) to a torque of 250 6 14 N.m (185 6 10 lb ft).

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Differentail Thrust Pin Gap Adjustment

Install the thrust pin in the differential housing without the O-ring seal. Put cover (2) in position on the differential housing, and install the bolts. Tighten the bolts evenly until the thrust pin is against the bearing cap. Use a feeler gauge, and measure the gap between the differential housing and cover (2). Use this measurement minus 0.05 6 0.03 mm (.002 6 .001 in) for the shim thickness needed. Remove cover (2) and the thrust pin from the differential housing.

Put the O-ring seal in position on thrust pin (4). Put clean oil on the O-ring seal. Install thrust pin (4) in the differential housing. Put the correct amount of shims (3) found in Step 4 in position, and install cover (2) on the differential housing. Note: The thrust pin will make contact with the bearing cap.

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General Torque Information Warning

Mismatched or incorrect fasteners can result in damage or malfunction, or possible injury. Take care to avoid mixing metric dimensioned fasteners and inch dimensioned fasteners. Exceptions to these torques are given in the Service Manual, if necessary. Prior to installation of any hardware, ensure that components are in near new condition. Bolts and threads must not be worn or damaged. Threads must not have burrs or nicks. Hardware must be free of rust and corrosion. Clean the hardware with a noncorrosive cleaner. Do not lubricate the fastener threads except for the rust preventive. The rust preventive should be applied by the supplier of that component for purposes of shipping and storage. Other applications for lubricating components may also be specified in the Service Manual.

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Standard Torque for Metric Fasteners

Thread Size Metric M6 M8 M10 M12 M14 M16 M20 M24 M30 M36 Thread Size Metric M6 M8 M10 M12 M16 M20 M24 M30 M36

Metric Nuts and Bolts Standard Torque 12 6 3 N.m (9 6 2 lb ft) 28 6 7 N.m (21 6 5 lb ft) 55 6 10 N.m (41 6 7 lb ft) 100 6 20 N.m (75 6 15 lb ft) 160 6 30 N.m (120 6 22 lb ft) 240 6 40 N.m (175 6 30 lb ft) 460 6 60 N.m (340 6 44 lb ft) 800 6 100 N.m (590 6 75 lb ft) 1600 6 200 N.m (1180 6 150 lb ft) 2700 6 300 N.m (2000 6 220 lb ft) Metric Taperlock Studs Standard Torque 8 6 3 N.m (6 6 2 lb ft) 17 6 5 N.m (13 6 4 lb ft) 35 6 5 N.m (26 6 4 lb ft) 65 6 10 N.m (48 6 7 lb ft) 110 6 20 N.m (80 6 15 lb ft) 170 6 30 N.m (125 6 22 lb ft) 400 6 60 N.m (300 6 44 lb ft) 750 6 80 N.m (550 6 60 lb ft) 1200 6 150 N.m (880 6 110 lb ft)

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Standard Torque for Inch Fasteners

Thread Size Inch 1/4 5/16 3/8 7/16 1/2 9/16 5/8 3/4 7/8 1 1 1/8 1 1/4 1 3/8 1 1/2 Thread Size Inch 1/4 5/16 3/8 7/16 1/2 5/8 3/4 7/8 1 1 1/8 1 1/4 1 3/8 1 1/2

Inch Nuts and Bolts Standard Torque 12 6 3 N.m (9 6 2 lb ft) 25 6 6 N.m (18 6 4 lb ft) 47 6 9 N.m (35 6 7 lb ft) 70 6 15 N.m (50 611 lb ft) 105 6 20 N.m (75 6 15 lb ft) 160 6 30 N.m (120 6 22 lb ft) 215 6 40 N.m (160 6 30 lb ft) 370 6 50 N.m (275 6 37 lb ft) 620 6 80 N.m (460 6 60 lb ft) 900 6 100 N.m (660 6 75 lb ft) 1300 6 150 N.m (960 6 110 lb ft) 1800 6 200 N.m (1320 6 150 lb ft) 2400 6 300 N.m (1780 6 220 lb ft) 3100 6 350 N.m (2280 6 260 lb ft) Inch Taperlock Studs Standard Torque 8 6 3 N.m (6 6 2 lb ft) 17 6 5 N.m (13 6 4 lb ft) 35 6 5 N.m (26 6 4 lb ft) 45 6 10 N.m (33 6 7 lb ft) 65 6 10 N.m (48 6 7 lb ft) 110 6 20 N.m (80 6 15 lb ft) 170 6 30 N.m (125 6 22 lb ft) 260 6 40 N.m (190 6 30 lb ft) 400 6 60 N.m (300 6 44 lb ft) 525 6 60 N.m (390 6 44 lb ft) 750 6 80 N.m (550 6 60 lb ft) 950 6 125 N.m (700 6 90 lb ft) 1200 6 150 N.m (880 6 110 lb ft)

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Reference Material

Service Training 773D Off highway Truck

Conversion Tables LINEAR MEASURE Inches x 2.54 = Centimeters Yards x 0.9144 = Meters

Centimeters x .3937 = inches Metres x 3.2808 = Feet SQUARE MEASURE

Sq. Inches x 6.452 = Sq. Cent. metrs

Cent. mtrs. x 0.155 = Sq. Inches

Sq. Feet x 0.0929 = Sq. Meters

Sq. Metres x 10.764 = Sq. Feet

CUBIC MEASURE Cu. Feet x 28.316 = Litres Cu. Yards x 0.7646 = Cu Metres U.S. Pints x 0.473 = Litres U.S. Quarts x 0.946 = Litres Litres x 0.2642 = Gallons (USA)

Cu. Metres x 35.314 = Cu. Feet Cu. Metres x 1.308 = Cu. Yards Litres x 2.1134 = U.S. Pintss Litres x 1.0567 = U.S. Quarts Gallons x 3.785 = Litres

Litres x 0.2199 = Gallons (UK)

Gallons x 4.546 = Litres WEIGHTS

Pounds x 0.45359 = Kilograms

Kilograms x 2.2046 = Pounds

Tonnes x 0.9842 = Tonnes

Tonnes x 1.0161 = Tonnes

PRESSURE & TORQUE Lbs. Per. Sq. Inch x 0.0703 = Kgs. per Sq. Centimeter Kilopascal x 0.145 = Pounds per square inch Newton metres x 0.7376 = Pound feet

Kgs. per Sq. Centimeter x 14.244 = Lbs. per Sq. Inch Pounds per square inch x 6.895 = kilopascal Pound feet x 1.356 = Newton metres

Newton metres x 0.1019 = KGF metre

KGF metre x 9.807 = Newton metres

TEMPERATURE 5 x (F° - 32) 9

9 x C°

= C°

5

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+ 32 = F°