722.9 Automatic Transmission

722.9 Automatic Transmission

Tech 331, 722.9 (F,hayward),1/27/04

Objectives ?

To know the advantages and Features of the 722.9 transmission

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To identify new components

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To understand maintenance concerns

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To know location / function of major components

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To explain shift members

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To explain electronics

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Features 722.9 h

Electronically controlled 7-speed

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Seven forward and two reverse gears

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Fully integrated transmission control unit (Flash capable)

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Torque converter operates in open or slip mode in all seven forward gears

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Gear ratios are achieved with four multi disc brakes and three multi disc clutches (no free-wheeling units)

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2 simple and 1 ravigneaux gear set

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Advantages ?

Improved shift comfort/driving pleasure q

Quicker shifts 0.1 – 2.5 seconds

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37 to 74 mph times shortened by between 23% and 28%

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Reduce fuel consumption (up to 4%)

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Reduce maintenance cost

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Increased service life and reliability

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Flexible adaptation to vehicle and engine

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Driver can choose between “S” and “C” mode 4

Transmission Designation Transmission 722. 9 01 Version, e.g. matching to the respective engine Sales designation Automatic transmission for passenger cars

Sales Designation W 7 A 700 Max. input torque in NM Version (internal) Number of forward gears Hydraulic torque converter 5

Transmission Fluid ?

The 722.9 transmission requires a newly developed transmission fluid. MB part number A001 989 45 03 q

Higher friction constancy

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Higher thermal stability

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Improved temperature behavior

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Lifetime fill

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Can be used in 722.3 / .4 / .5 / .6

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Must be used in 722.9

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Major Components (7 G-Tronic)

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Major Components Legend 1. Park pawl gear 2. Turbine wheel 3. Stator 4. Impeller 5. Transmission housing ventilation 6. Oil pump 7. B1 multi-disk brake 8. K1 multi-disk clutch 9. Ravigneaux gear set 10. B3 multi-disk brake 11. K2 multi-disk clutch 12a. Front simple planetary gear set 12b. Rear simple planetary gear set

13. BR multi-disk brake 14. K3 multi-disk clutch 15. B2 multi-disk brake 16. Torque converter lockup clutch 17. Torque converter housing 18. Exciter ring for torque measurement 19. Ring magnet for torque measurement 20. Ring magnet for torque measurement 21. Electro hydraulic control unit 22. Range selector lever

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Transmission Housing

• Magnesium housing (lighter weight) requires aluminum bolts any aluminum bolt must be replaced if removed! • No power tools • Adhere to angle torques 9

Ravigneaux Gear Set Advantages of ravigneaux gear set • Shifting under load • Production of several gear ratios • Constant engagement of gearing • Easier reversal of rotational direction • High efficiency • Compact construction • Combines 2 simple planetary gear sets into one unit

1. 2. 3. 4.

Short planetary gear Long planetary gear Sun gear Planetary gear carrier

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Multi-disk Clutch/Brake • Transferable power of multi-disk clutch increased • Friction disks of K1, K2 and K3 now have single-sided friction disks • Cost advantage • Less installation space required • Higher load capability • Lower mass

1. A. B.

Friction lining on one side of metal carrier Metal carrier outer disk Metal carrier inner disk

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Fully Integrated Transmission Control

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Fully Integrated Transmission Control Legend 11 21b 21c 21d 31 32 Y3/8 Y3/8n1 Y3/8n2 Y3/8n3 Y3/8n4

Plug connection Valve body Intermediate panel Shift housing Float 1 Float 2 Electric control module Turbine rpm sensor Internal rpm sensor Output rpm sensor Transmission control unit Y3/8s1 Selection range sensor

Y3/8y1 Y3/8y2 Y3/8y3 Y3/8y4 Y3/8y5 Y3/8y6 Y3/8y7 Y3/8y8

Working pressure control solenoid valve K1 clutch control solenoid valve K2 clutch control solenoid valve K3 clutch control solenoid valve B1 brake control solenoid valve B2 brake control solenoid valve B3 brake control solenoid valve Torque converter lockup clutch control solenoid valve

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Electronic Transmission Control Unit Inputs Monitors and shifts transmission based on: • Vehicle speed • Vehicle load • Accelerator position • Selector lever position • Electronic selector lever module (N15/5) • Transmission condition (aging)

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Electronic Transmission Control Unit Inputs Internal inputs effecting solenoid valves • Turbine rpm sensor (active) • Internal rpm sensor (active) • Output rpm sensor (hall) • Transmission oil temperature sensor

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Electronic Transmission Control Unit • Mounted directly on the hydraulic control unit • Married to vehicle – ETC unit calibrated to hydraulic control unit on flow bench • Information received over CAN with ME – Engine rpm, coolant temperature, accelerator position, engine load – ESP signals – Cruise control signals • Information received from ETC – Position of selector range valve – Transmission oil temperature – Transmission internal revolutions – Transmission output rpm

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Electronic Transmission Control Unit Functions From data received Transmission control unit calculates • Driver and vehicle specific shift points • Hydraulic pressures • Torque converter lockup clutch • Corrects for atmospheric pressure, shifting and pressure • Driver actions; accelerator movement, manual touch frequency, longitudinal and lateral acceleration • Software can be updated, referred to as flashing, carried out using SDS 17

Speed Sensor Locations • Turbine speed sensor monitors rotational speed of internal ravigneaux gear • Internal speed sensor measures rotational speed front planetary gear • Output speed sensor measures transmission output speed park pawl • Output speed sensor increases reaction time

1. Ring magnet 2. Cylinder flange with integrated ring magnet 3. Exciter ring 4a. Park pawl gear

Y3/8n1 Y3/8n2 Y3/8n3

Turbine rpm sensor Internal rpm sensor Output rpm sensor 18

Shift Program Basic shift program can be influenced using selector button on the electronic selector lever control module • Driver can choose transmission modes, “C” (comfort) or “S” (sport) • Each mode has different shift strategies • Transmission mode “S” (firmer faster shift) as opposed to mode “C” engine rpm level raised • Switch position transmitted by electronic selector module over CAN-C to ETC

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Shift Programs The adjustment of the shift programs takes place by moving the characteristic dependent on: • Vehicle payload • Change in engine load • Pedal movement • Slow

Unintended downshifts in high vehicle speed range are prevented

• Fast release

The up-shift to the next gear is prevented and is only allowed again at low lateral vehicle acceleration

• Kick-down

Bringing forward and raising of the downshift characteristic in the upper vehicle speed range 20

Shifting Process • ETC controls solenoid valves electronically • Valves sit in hydraulic shift plate • Shift plate implements hydraulic function • ETC precisely adjusts pressure during shift phase, which leads to increase in shift quality • Main function of ETC is to evaluate inputs relevant to transmission function and actuate eight hydraulic valves, which set working pressure

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Solenoid Valves Internal output signal or actuation of control solenoid valves • Torque converter lockup clutch valve (Y3/8y8) normally closed in default no pressure • Working pressure valve (Y3/8y1) normally open in default allows pressure • K2 clutch valve (Y3/8y3) normally open in default allows pressure • B2 brake valve (Y3/8y6) normally closed in default no pressure

Y3/8y8 – Torque converter lockup clutch valve Y3/8y1 – Working pressure valve Y3/8y3 – K2 clutch valve Y3/8y6 – B2 brake valve

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Solenoid Valves Internal output signal or actuation of control solenoid valves • K1 clutch valve (Y3/8y2) normally open in default allows pressure • B1 brake valve (Y3/8y5) normally open in default allows pressure • B3 brake valve (Y3/8y7) normally closed in default no pressure • K3 clutch valve (Y3/8y4) normally open in default allows pressure

Y3/8y2 – Y3/8y5 – Y3/8y7 – Y3/8y4 –

K1 clutch valve B1 brake valve B3 brake valve K3 clutch valve

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722.9 Down Shifting

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Shift Chart

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