Automatic Transmission -- Basic Knowledge -- 251 Chassis: Other Mercedes-Benz R-class W251 facelift

Automatic transmission (AT), gear ratios - GF27.10-P-0001-01SX

Transmission 722.9 in model 164.177, 216, 221, 251.0/1

Automatic transmission (AT), transmission modes - GF27.10-P-0001-06AHZ

Illustration shows instrument cluster (A1), model 164

Scheme 220

Gear indicator in instrument cluster in sport transmission mode "S" and comfort transmission mode "C"

It shows the driver the shift range currently selected "1, 2, 3, 4, 5, 6" or the selector lever position "P, R, N, D".

Gear indicator in instrument cluster in manual transmission mode "M" (except code (494) USA version)

It shows the driver the engaged gear "1,2, 3, 4, 5, 6, 7" or the selector lever position "P, R, N".

Transmission mode display in instrument cluster

It indicates to the driver the program selection Sport "S", Comfort "C" or Manual "M" performed at the transmission modes switch (N72/1s32).

The data come from the fully integrated transmission control (VGS) control unit (Y3/8n4) and from the intelligent servo module for DIRECT SELECT (A80) via the engine compartment CAN.

4 different functions can be selected using the DIRECT SELECT gear selector switch (S16/13) and 3 different transmission modes using the transmission mode switch (N72/1s32).

Selector lever positions

"P" Park lock and start position

"R" Reverse gear

"N" Neutral and start position (no power transmission, vehicle can move freely)

"D" Drive (all 7 forward gears are available)

Upshifting and downshifting

Upshifting and downshifting takes place via the PLUS steering wheel gear shifter (S111/1) and MINUS steering wheel gear shifter (S110/1).

Press +: Upshift by one gear at a time. The shift range is expanded simultaneously in transmission modes "C" and "S".

Press and hold: Direct change to gear range "D".

Press -: Downshift by one gear at a time. The shift range is limited simultaneously in transmission modes "C" and "S".

Press and hold: The transmission changes into a shift range from which the vehicle can be accelerated or slowed down favorably.

If the shift range is restricted, upshifts occur close to the engine cutoff speed

Scheme 221

View of center console, model 164.8

Scheme 222

Transmission mode switch

The following transmission modes can be selected

Comfort transmission mode "C"

Starting off always in 2nd gear except in 1st gear range. The gear changes take place at lower engine speed.

Sport transmission mode "S"

Starting off in 1st gear for all driving situations.

Manual transmission mode "M"

Direct gear selection by means of the steering wheel gear shifter MINUS and steering wheel gear shifter PLUS.

When kick-down is actuated the upshifts and downshifts take place as in transmission mode Sport "S"

Automatic transmission (AT), features - GF27.10-P-0001-14GZ

Transmission 722.9 in model 164.1/8, 216, 221, 251.0/1

The following features differentiate transmission 722.9 from transmission 722.6

1. The transmission features 7 forward gears and 2 reverse gears.
2. A Ravigneaux gear set and 2 single planetary gear systems are used and thus other ratios are achieved.
3. The fully integrated transmission control (VGS) control unit (Y3/8n4) is located in the electric controller unit (VGS) (Y3/8). The transmission oil is therefore continuously flushed around the outside of the control unit which ensures the control unit is cooled.
4. The transmission oil temperature is recorded by the transmission oil temperature sensor (VGS) (Y3/8s2) installed in the fully integrated transmission control (VGS) control unit.
5. The number of interfaces to the wiring harness has been reduced due to the new position of the fully integrated transmission control (VGS) control unit.
6. Transmission 722.9 is therefore available as a compact assembly unit.
7. A torque converter lockup clutch with torsional dampers, which is slip-controlled in all 7 forward gears, is used.
8. The disks used on the multidisk clutches and 2 multidisk brakes are single-sided disks. The friction lining is only applied to one side on this version.
9. 3 sensors are fitted for recording RPM. This increases ease of shifting and reduces the reaction time during the shift operations.
10. It is possible to update (flashing) the control unit software in transmission 722.9 as and when required. This flash-updating is carried out using STAR DIAGNOSIS.

Automatic transmission (AT), updating the transmission control unit by flash-updating - GF27.10-P-0001-15AHZ

Diagnosis Assistance System (DAS)

Scheme 223

On transmission 722.9 the transmission software used can be exchanged (replaced) by a more current version. This updating procedure is referred to as flashing and is carried out using the DAS.

Automatic transmission (AT), updating the transmission control unit by flash-updating - GF27.10-P-0001-15GZ

Transmission 722.9 in model 164.1/8, 251.0/1

Shown on model 164.1

Scheme 224

On transmission 722.9 the transmission software used can be exchanged for a more up-to-date version. This updating is described as flashing and is carried out using STAR DIAGNOSIS.

Automatic transmission (AT), gear selector switch positions - GF27.10-P-0001-18RT

Transmission 722.9 in model 164.177, 251.0/1

Shows model 251.022

Scheme 225

The gear selector switch DIRECT SELECT can be moved to 4 different positions.

The gear selector switch positions refer to

P Park lock and start position

R Reverse gear

N Neutral and start position (No power transmission takes place. The vehicle is not in gear.)

D All 7 forward gears are available.

Transmission mode, model 251.022/065/075/122/165/175

The transmission mode switch (N72/1s32), which is located in the upper control panel control unit (N72/1), is used to switch between 2 transmission modes.

Transmission mode switch

Sport program "S"

1. Driving in 1st gear for all driving situations
2. The gears are completely disengaged.

Comfort program "C"

1. Starting off always in 2nd gear (except in 1st gear shift range).
2. The gears are not completely disengaged.

If kickdown is actuated the gears are shifted up and down as for the sport program "S"

Shift range limitation

In gear selector switch position "D" the shifting range can be limited using the left steering wheel gear shifter (S110/2) and right steering wheel gear shifter (S111/2).

In the limited shifting range an upshift is authorized close to the engine limit speed

Transmission mode, on model 164.177, 251.077/177

Using the transmission mode switch (N72/1s32), which is located in the upper control panel control unit (N72/1), it is possible to choose between 3 transmission modes.

Transmission mode switch

Sport program "S"

1. Driving in 1st gear for all driving situations
2. The gears are completely disengaged.

Comfort program "C"

1. Starting off always in 2nd gear (except in 1st gear shift range).
2. The gears are not completely disengaged.

If kickdown is actuated the gears are shifted up and down as for the sport program "S"

Manual program "M"

1. Direct gear selection possible by means of steering wheel gear shifter MINUS (S110/1)
2. Direct gear selection possible by means of steering wheel gear shifter PLUS (S111/1)

Shift range limitation

In gear selector switch position "D" the shift range can be limited via the steering wheel gear shifter MINUS and via the steering wheel gear shifter PLUS.

In the limited shifting range an upshift is authorized close to the engine limit speed

Scheme 226

Automatic transmission (AT), function - GF27.10-P-0001AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of Model Year 2009/Modification year 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of Model Year 2009/Modification Year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of model year 2009/modification year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of model year 2009/modification year 08

Automatic transmission (AT), general

Transmission 722.9 is an electronically controlled automatic transmission with 7 forward gears and 2 reverse gears. The ratios for the gear stages are achieved by planetary gear sets. All the transmission functions and components for this transmission are combined in one assembly module.

The integration of the electric controller unit (VGS) (Y3/8) in the transmission means that the interfaces to the wiring harness have been minimized. This improves the shift quality, increases the service life and reliability and also lowers maintenance costs.

The transmission can be subdivided into the following assemblies

1. Torque converter with torsional damper and torque converter lockup clutch
2. Oil pump for generating the necessary oil pressure and for reliable lubrication of the actuators and bearing points
3. Transmission housing with mechanical transmission components (planetary gear sets, park pawl, multidisk clutches and multidisk brakes) and controller unit

Data is exchanged with the following control units via the engine compartment CAN (CAN-C)

1. Instrument cluster (A1)
2. Intelligent servo module DIRECT SELECT (A80)
3. CDI control unit (N3/9) (on diesel engines)
4. ME-SFI [ME] control unit (N3/10) (on gasoline engines)
5. ESP control unit (N47-5)
6. EIS [EZS] control unit (N73)
7. Steering column module (N80)

Further partial functions are described in separate documents

1. Transmission control, function
2. Key-P function
3. Gear shift, function
4. Power flow, function

Automatic transmission (AT), function - GF27.10-P-0001RT

TRANSMISSION 722.9 in MODEL 251.0/1 up to Model Year 8

Scheme 227

Scheme 228

Networking of components, shown on engine 113

Transmission 722.9 is an electronically controlled automatic transmission with 7 forward gears and 2 reverse gears. All the transmission functions and transmission components for this automatic transmission are combined in one assembly module. Integrating the electrohydraulic controller unit in transmission 722.9 minimizes the number of interfaces to the wiring harness. The electrohydraulic controller unit is installed below the transmission housing; the transmission oil is continuously flushed around the outside of the controller unit, which amongst other things, ensures the controller unit is cooled.

Transmission 722.9 can be roughly divided into the following component groups

1. Torque converter with torsional damper and torque converter lockup clutch.
2. Oil pump to produce the necessary oil pressure and for reliable lubrication of the actuators and bearing points.
3. The transmission housing for the mechanical transmission components and electrohydraulic controller unit. The transmission housing is made of a light alloy.
4. The mechanical transmission components, consisting of a Ravigneaux gear set, front single planetary gear set, rear single planetary gear set and a park pawl. Additionally, a multi-disk clutch K1, multi-disk clutch K2, multi-disk clutch K3, multi-disk brake B1, multi-disk brake B2, multi-disk brake B3 and the BR multi-disk brake are also integrated. Single-sided disks are used on multidisk clutch K1, on multidisk clutch K2 and on multidisk clutch K3 Single-sided disks are also used on multidisk brake B1 and on multidisk brake B3 On this type of lamella the friction lining is only applied on one side. Among other things, this improves heat distribution in the disk pack, the design of the disk pack is more compact, the load-bearing capacity is increased and the mass is reduced. For the multi-disk brake B2 and BR multi-disk brake disks coated on both sides are also used.
5. Electrohydraulic controller unit consisting of the electric controller unit VGS (Y3/8), valve body and valve housing.

The following information are taken into account when shifting the drive positions

1. Vehicle speed
2. Vehicle load
3. Driving resistance
4. Position and operating speed of accelerator pedal
5. Selected drive position and engaged gear
6. Selected transmission mode
7. Oil temperature and other information about the status of the transmission
8. Further signals which are available via the Controller Area Network bus class C (engine compartment) (CAN-C)

Data is exchanged with the following control units via CAN-C

1. Instrument cluster
2. Intelligent servo module for DIRECT SELECT
3. CDI control unit (N3/9)
4. ME control unit
5. ESP control unit
6. Upper control panel control unit
7. EIS [EZS] control unit
8. Steering column module
9. Central gateway control unit

This involves the processing of the following data from other systems

Intelligent servo module for DIRECT SELECT

1. Actual position of range selector lever

CDI control unit (with engine 642)

1. Start-off in 1st gear, aids engine warm-up
2. Shift line displacement, aids engine warm-up
3. Specified gear, lower and upper limit, aids engine warm-up
4. Shift line displacement, dependent on load condition of diesel particulate filter (DPF), a heavily loaded DPF results in slightly lower upshift speed for full-load and kick-down upshifts
5. Emergency operation of the common rail diesel injection, the pedal value is limited to approx. 20 %, the driveability of the vehicle is assured
6. Engine coolant temperature, used as substitute value in event of malfunction in transmission oil temperature sensor (VGS) (Y3/8s2)
7. Engine oil temperature, shift limitation is canceled
8. Requirement torque for Electronic Stability Program (Electronic-Stability-Program) (ESP), torque reduction or torque increase taking into account directional stability and road adhesion
9. Kickdown
10. Request "Torque converter lockup clutch OPEN" to increase the engine speed in the warm-up phase of the engine
11. Pedal value
12. Engine torque
13. Engine idle specified speed for the actuation of the torque converter lockup clutch
14. Engine-speed limitation function active, adaptations are deactivated in the fully integrated transmission control (VGS) control unit
15. Engine speed, for slip calculation of torque converter lockup clutch and for start of pressure calculation by fully integrated transmission control (VGS) control unit

ME-SFI [ME] control unit (except engine 642)

1. Active downshift for heating up the catalytic converter (TWC)
2. Shift line displacement to heat up the catalytic converter
3. Emergency operation of ME gasoline injection and ignition system (motor electronics) (ME), the pedal value is restricted to approx. 20 %, the vehicle driveability is thus assured
4. Engine torque
5. Start-up in 1st gear for warming up catalytic converter
6. Engine coolant temperature, used as substitute value in event of malfunction in transmission oil temperature sensor (VGS)
7. Engine oil temperature, shift limitation is canceled
8. Request "Torque converter lockup clutch OPEN" to increase engine speed in the warm-up phase of the engine
9. Engine idle specified speed for the actuation of the torque converter lockup clutch
10. Engine speed, for slip calculation of torque converter lockup clutch and for start of pressure calculation by fully integrated transmission control (VGS) control unit
11. Engine-speed limitation function active, adaptations are deactivated in the fully integrated transmission control (VGS) control unit
12. Kickdown
13. Selected torque ESP, torque reduction or increase taking directional stability and road adhesion into account
14. Specified gear, lower and upper limit to heat up the catalytic converter
15. Pedal value

ESP control unit

1. BAS release switch (A7/7s1), change of shift strategy, brake the vehicle, the fully integrated transmission control (VGS) shifts down earlier
2. Set brake torque, change of shift strategy, brake the vehicle, the fully integrated transmission control (VGS) shifts down earlier
3. Wheel speeds and direction of rotation, substitute values in event of malfunction of output speed sensor (VGS) (Y3/8n3)
4. ESP request shift into "N" (neutral), power flow interruption, transmission/rear axle
5. Vehicle lateral acceleration at center of gravity, adaptation of shift strategy, detection of dynamic driving style
6. Cruise control controls, a special shifting strategy for cruise control mode is filed in the fully integrated transmission control (VGS) control unit

Upper control panel control unit

1. Transmission mode switch

EIS [EZS] control unit

1. Refrigerant compressor (A9) ON
2. Circuit 50, influencing fault memory
3. Torque requirement of refrigerant compressor, torque correction

Steering column module

1. Signal from steering wheel gear shifter MINUS (S110/1), on model 251.077/177
2. Signal from steering wheel gear shifter PLUS (S111/1), on model 251.077/177
3. Signal from left steering wheel gear shifter (S110/2), except model 251.077/177
4. Signal from right steering wheel gear shifter (S111/2), except model 251.077/177
5. Signal from DIRECT SELECT gear selector switch (S16/13)

Central gateway control unit

1. Diagnosis

The following information is passed to other systems

Instrument cluster

1. Gear selector switch position for multifunction display (A1p13)
2. Transmission mode selection for multifunction display
3. Pre-selected shift range for multifunction display

Intelligent servo module for DIRECT SELECT

1. Driver selected gear selector position
2. Actual position of transmission
3. Specified position of range selector lever

CDI control unit (with engine 642)

1. Engine torque requests, engine intervention when shifting
2. Limp-home of fully integrated transmission control (VGS)
3. Starter lockout release in selector lever position "P", "N"
4. Transmission variant, recognition of basic variants, difference in gear ratios
5. Status of torque converter lockup clutch
6. Actual gear and target gear, gear engaged, gear to be shifted, can be shown using STAR DIAGNOSIS

ME-SFI [ME] control unit (except engine 642)

1. Starter lockout release in gear selector switch position "P", "N"
2. Status of torque converter lockup clutch
3. Actual gear engaged and target gear, i.e. engaged gear, gear to be engaged, can be shown via STAR DIAGNOSIS
4. Transmission variant, recognition of basic variants, difference in gear ratios
5. Engine torque requests, engine intervention when shifting
6. Limp-home of fully integrated transmission control (VGS)

ESP control unit

1. Wheel torque factor, overall gear ratio
2. Transmission variant, recognition of basic variants, difference in gear ratios
3. Actual gear engaged and target gear, i.e. engaged gear, gear to be engaged, can be shown via STAR DIAGNOSIS

Central gateway control unit

1. Gear selector switch position for actuation of backup lamp function
2. Diagnosis

Power flow, function - GF27.10-P-2009AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of model year 2009/CY 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of model year 2009/CY08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of model year 2009/CY08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of model year 2009/CY08

Scheme 229

Schematic illustration of power transmission on 4x2 drive, model 164.156, model 251.026/054/056/126/154/156

Scheme 230

Schematic illustration of power transmission 4x4 drive, model 164.120/122/124/125/128/172/186/822/824/825/828/871/886, 251.020/022/065/072/122/124/125/165/172/175

Power transmission, general

"Power flow" refers to the transmission paths of driving power and engine torque. The engine torque is transferred to the drive wheels via the following mechanical and hydraulic connections

1. Torque converter
2. Automatic transmission
3. Propeller shafts
4. Rear axle differential
5. Transfer case (model 164.120/122/124/125/128/172/186/822/824/825/828/871/886, 251.020/022/065/072/122/124/125/165/172/175)
6. Front differential (model 164.120/122/124/125/128/172/186/822/824/825/828/871/886, 251.020/022/065/072/122/124/125/165/172/175)

Power is transferred in the torque converter via the driven impeller by diverting hydraulic fluid to the turbine wheel which is connected to the transmission input shaft.

If the torque converter lockup clutch is engaged, the power flows via this mechanical connection to the transmission input shaft.

Via the gear wheels of the individual planetary gear sets, the torques coming from the converter, depending on the gear ratio and shift elements actuated, are passed on to the transmission output shaft with the help of the multidisk clutches and multidisk brakes. A reduction of the output speed in the low gears provides lower vehicle speeds with high tractive forces and drive torques at the drive wheels.

Further partial functions are described in separate documents

1. Power flow in 1st gear, function
2. Power flow in 2nd gear, function
3. Power flow in 3rd gear, function
4. Power flow in 4th gear, function
5. Power flow in 5th gear, function
6. Power flow in 6th gear, function
7. Power flow in 7th gear, function
8. Power flow in reverse gear, transmission mode "S", function
9. Power flow in reverse gear, transmission mode "C", function

Power flow, function - GF27.10-P-2009GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 204.0, 216, 221, 251.0/1 up to Model Year 08/modification year 07

Scheme 231

Schematic representation, shown on model 164

Power transmission, function

The term "power flow" refers to the transmission paths of driving power and engine torques. Via the mechanical/hydraulic connection of the engine, torque converter, the downstream automatic transmission and transfer case the engine torques are transmitted to the drive wheels and converted in the transmission via several planetary gear sets.

Power is transferred in the torque converter via the driven impeller by diverting hydraulic fluid to the turbine wheel, which is connected to the transmission input shaft.

When the torque converter lockup clutch is engaged, power is transmitted via this mechanical connection. Via the gear wheels of the individual planetary gear set the torques going out from the torque converter, depending on the gear ratio and shift elements actuated, are passed on to the output shaft using multi-disk clutches and multi-disk brakes.

A reduction of the output speed in the low gears provides lower vehicle speeds with high tractive forces and drive torques at the drive wheels.

Kick-down, function - GF27.10-P-2010GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 251.0/1 up to Model Year 8

Shown with engine 113

Scheme 232

Kickdown, function

The driver's wish for the maximum vehicle acceleration is met by the kickdown function.

The kick-down function is activated from a pedal travel at the electronic accelerator > approx. 90 %.

When actuating the electronic accelerator, the driver notices an increase in back pressure at the kickdown point. For this purpose a kick-down simulator is integrated in the electronic accelerator.

The "Kickdown" signal is sensed by the accelerator pedal sensor, read by the CDI control unit (N3/9) or ME-SFI [ME] control unit and transmitted over Controller Area Network bus class C (engine compartment) (CAN-C) to the fully integrated transmission control (VGS) control unit.

Based on this information the fully integrated transmission control (VGS) control unit actuates the control solenoid valves so that the upshifts and downshifts take place at higher engine speeds in order to achieve maximum performance.

Ignition lock locking, function - GF27.10-P-3003GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 216, 221, 251.0/1 up to Model Year 8

Ignition switch lock, function

The EIS [EZS] control unit (N73) locks the transmitter key (A8/1) manual as of "terminal 15R ON".

As soon as the vehicle speed exceeds the speed threshold of 8 km/h, the EIS [EZS] control unit prevents removal of the transmitter key as gear selector switch position "P" (Key-P function) cannot be automatically engaged by the intelligent servo module for DIRECT SELECT (A80).

As long as the vehicle speed remains under the speed threshold, the transmitter key can be removed and the following gear selector switch position is automatically switched by the intelligent servo module for DIRECT SELECT

1. Gear selector switch position "P", on model 221 up to 31.8.06, model 164 and model 251 up to 31.5.07
2. Gear selector switch position "N", on model 216, model 221 as of 1.9.06, model 164 and model 251 as of 1.6.07 On model 216, model 221 as of 1.9.06, model 164 and model 251 as of 1.6.07 the gear selector switch position "P" is switched automatically by the Intelligent servo module for DIRECT SELECT as soon as the driver door is opened.

Power flow in 1st gear, function - GF27.10-P-3011AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of Model Year 09/Modification year 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of Model Year 09/Modification Year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of Model Year 09/Modification year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of Model Year 09/Modification year 08

Scheme 233

Function requirements for power flow in 1st gear, general

1. Circuit 87 ON
2. Engine running

Power flow in 1st gear, general

The following multi-disk brakes and multi-disk clutches are engaged

1. Multidisk brake B2 (43)
2. Multidisk brake B3 (45)
3. Multidisk clutch K3 (48)

In 1st gear, the power flows through the following gear sets

1. Ravigneaux gear set
2. Rear single planetary gear set
3. Front single planetary gear set

Ravigneaux gear set

The small ring gear (5) is driven via the transmission input shaft. The long planetary gears (50) drive the short planetary gears (49) which roll in the stalled large ring gear (8). An increased torque and reduced RPM occur as a result which are transmitted to the dual planet carrier (6).

Rear single planetary gear set

The ring gear (9) rotates at the same speed due to the mechanical connection to the dual planet carrier (6). The planetary gears (51) and rotates at the same speed. The planetary gears (52) roll over the stalled sun gear (11) and transmit the rotary motion to the planet carrier (10).

Front single planetary gear set

The ring gear (12) has a mechanical connection to the planet carrier (10) and rotates at the same speed. The planetary gears (52) roll on the stalled sun gear (14) and transfer the increased torque and reduced rotational speed to the transmission output shaft via the planet carrier (13). The transmission output shaft thus rotates with reduced transmission input speed in the direction of rotation of the engine.

Power flow in 1st gear, function - GF27.10-P-3011GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 204.0, 216, 221, 251.0/1 up to Model Year 8

Scheme 234

The Ravigneaux gear set consists of the following components

1. Short planetary gears (49)
2. Long planetary gears (50)
3. Small ring gear (5)
4. Dual planet carrier (6)
5. Sun gear (7)
6. Large ring gear (8)

The front single planetary gear set consists of the following components

1. Planetary gears (52)
2. Ring gear (12)
3. Planet carrier (13)
4. Sun gear (14)

The rear single planetary gear set consists of the following components

1. Planetary gears (51)
2. Ring gear (9)
3. Planet carrier (10)
4. Sun gear (11)

Power flow in 1st gear, function

The following multi-disk brakes and multi-disk clutches are engaged

1. Multidisk brake B2
2. Multidisk brake B3
3. Multidisk clutch K3

Ravigneaux gear set

The small ring gear is driven via the transmission input shaft. The long planetary gears drive the short planetary gears, which roll in the stalled large ring gear. An increased torque and reduced RPM occur as a result and this is transmitted to the dual planet carrier.

Single rear planetary gear system

The ring gear (9) rotates at the same speed due to the mechanical connection to the dual planet carrier. The planetary gears (51) roll over the stalled sun gear (11) and transmit the rotary motion to the planet carrier (10).

Single front planetary gear system

The ring gear (12) has a mechanical connection to the planet carrier (10) and rotates at the same speed. The planetary gears (52) roll on the stalled sun gear (14) and transfer the increased torque and reduced rotational speed to the transmission output shaft via the planet carrier (13). The transmission output shaft thus rotates with reduced transmission input speed in the direction of rotation of the engine.

Power flow in 2nd gear, function - GF27.10-P-3012AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of Model Year 09/Modification year 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of Model Year 09/Modification Year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of Model Year 09/Modification year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of Model Year 09/Modification year 08

Scheme 235

Function requirements for power flow in 2nd gear, general

1. Circuit 87 ON
2. Engine running

Power flow in 2nd gear, general

The following multi-disk brakes and multi-disk clutches are engaged

1. Multidisk brake B1 (42)
2. Multidisk brake B2 (43)
3. Multidisk clutch K3 (48)

In 2nd gear, the power flows through the following gear sets

1. Ravigneaux gear set
2. Rear single planetary gear set
3. Front single planetary gear set

Ravigneaux gear set

The small ring gear (5) is driven via the transmission input shaft. The long planetary gears (50) roll over the stalled sun gear (7) and transmit the increased torque and reduced rotational speed as a result to the dual planet carrier (6).

Rear single planetary gear set

The ring gear (9) rotates at the same speed due to the mechanical connection to the dual planet carrier (6). The planetary gears (51) and rotates at the same speed. The planetary gears (52) roll over the stalled sun gear (11) and transmit the rotary motion to the planet carrier (10).

Front single planetary gear set

The ring gear (12) has a mechanical connection to the planet carrier (10) and rotates at the same speed. The planetary gears (52) roll on the stalled sun gear (14) and transfer the increased torque and reduced rotational speed to the transmission output shaft via the planet carrier (13). The transmission output shaft thus rotates with reduced transmission input speed in the direction of rotation of the engine.

Power flow in 2nd gear, function - GF27.10-P-3012GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 204.0, 216, 221, 251.0/1 up to Model Year 8

Scheme 236

The Ravigneaux gear set consists of the following components

1. Short planet gears
2. Long planet gears
3. Small internal-geared wheel
4. Dual planet carrier
5. Sun gear (7)
6. Large internal-geared wheel

The front single planetary gear set consists of the following components

1. Planetary gears (52)
2. Internal-geared wheel (12)
3. Planet carrier (13)
4. Sun gear (14)

The rear single planetary gear set consists of the following components

1. Planetary gears (51)
2. Internal-geared wheel (9)
3. Planet carrier (10)
4. Sun gear (11)

Power flow in 2nd gear, function

The following multi-disk brakes and multi-disk clutches are engaged

1. Multidisk brake B1
2. Multidisk brake B2
3. Multidisk clutch K3

Ravigneaux gear set

The small ring gear is driven via the transmission input shaft. The long planetary gears roll over the stalled sun gear (7) and transmit the increased torque and reduced rotational speed to the dual planet carrier.

Single rear planetary gear system

The ring gear (9) rotates at the same speed due to the mechanical connection to the dual planet carrier. The planetary gears (51) roll over the stalled sun gear (11) and transmit the rotary motion to the planet carrier (10).

Single front planetary gear system

The internal-geared wheel (12) has a mechanical connection to the planet carrier (10) and rotates at the same speed. The planetary gears (52) roll on the stalled sun gear (14) and transfer the increased torque and reduced rotational speed to the transmission output shaft via the planet carrier (13). The transmission output shaft thus rotates with reduced transmission input speed in the direction of rotation of the engine.

Power flow in 3rd gear, function - GF27.10-P-3013AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of Model Year 09/Modification year 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of Model Year 09/Modification Year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of Model Year 09/Modification year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of Model Year 09/Modification year 08

Scheme 237

Function requirements for power flow in 3rd gear, general

1. Circuit 87 ON
2. Engine running

Power flow in 3rd gear, general

The following multi-disk brakes and multi-disk clutches are engaged

1. Multidisk brake B2 (43)
2. Multidisk clutch K1 (46)
3. Multidisk clutch K3 (48)

In 3rd gear, the power flows through the following gear sets

1. Ravigneaux gear set
2. Rear single planetary gear set
3. Front single planetary gear set

Ravigneaux gear set

Due to the engaged multi-disk clutch K1 (46) the components of the Ravigneaux gear set are locked together and pass on the transmission input torque and transmission input speed unchanged to the ring gear (9).

Rear single planetary gear set

The ring gear (9) drives the planetary gears (51). These roll over the stalled sun gear (11) and transmit the rotary motion to the planet carrier (10).

Front single planetary gear set

The ring gear (12) has a mechanical connection to the planet carrier (10) and rotates at the same speed. The planetary gears (52) roll on the stalled sun gear (14) and transfer the increased torque and reduced rotational speed to the transmission output shaft via the planet carrier (13). The transmission output shaft thus rotates with reduced transmission input speed in the direction of rotation of the engine.

Power flow in 3rd gear, function - GF27.10-P-3013GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 204.0, 216, 221, 251.0/1 up to Model Year 8

Scheme 238

The Ravigneaux gear set consists of the following components

1. Short planet gears
2. Long planet gears
3. Small internal-geared wheel
4. Dual planet carrier
5. Sun gear (7)
6. Large internal-geared wheel

The front single planetary gear set consists of the following components

1. Planetary gears (52)
2. Internal-geared wheel (12)
3. Planet carrier (13)
4. Sun gear (14)

The rear single planetary gear set consists of the following components

1. Planetary gears (51)
2. Internal-geared wheel (9)
3. Planet carrier (10)
4. Sun gear (11)

Power flow in 3rd gear, function

The following multi-disk brakes and multi-disk clutches are engaged

1. Multidisk brake B2
2. Multidisk clutch K1
3. Multidisk clutch K3

Ravigneaux gear set

Due to the engaged multidisk clutch K1 the components of the Ravigneaux gear set are locked together and pass on the transmission input torque and transmission input speed unchanged to the ring gear (9).

Single rear planetary gear system

The ring gear (9) drives the planetary gears (51). These roll over the stalled sun gear (11) and transmit the rotary motion to the planet carrier (10).

Single front planetary gear system

The internal-geared wheel (12) has a mechanical connection to the planet carrier (10) and rotates at the same speed. The planetary gears (52) roll on the stalled sun gear (14) and transfer the increased torque and reduced rotational speed to the transmission output shaft via the planet carrier (13). The transmission output shaft thus rotates with reduced transmission input speed in the direction of rotation of the engine.

Power flow in 4th gear, function - GF27.10-P-3014AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of Model Year 09/Modification year 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of Model Year 09/Modification Year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of Model Year 09/Modification year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of Model Year 09/Modification year 08

Scheme 239

Function requirements for power flow in 4th gear, general

1. Circuit 87 ON
2. Engine running

Power flow in 4th gear, general

The following multi-disk brakes and multi-disk clutches are engaged

1. Multidisk brake B2 (43)
2. Multidisk clutch K1 (46)
3. Multidisk clutch K2 (47)

In 4th gear, the power flows through the following gear sets

1. Ravigneaux gear set
2. Rear single planetary gear set
3. Front single planetary gear set

Ravigneaux gear set

Due to the engaged multi-disk clutch K1 (46) the components of the Ravigneaux gear set are locked together and pass on the transmission input torque and transmission input speed unchanged to the ring gear (9).

Rear single planetary gear set

The engaged multidisk clutch K2 (47) means that the RPM of the ring gears (9,12) are the same. As a result the rear single planetary gear system is locked and not actively involved in the gear ratio.

Front single planetary gear set

Due to the engaged multi-disk clutch K2 (47) the ring gear (12) is driven at transmission input speed. The planetary gears (52) roll on the stalled sun gear (14) and transfer the increased torque and reduced rotational speed to the transmission output shaft via the planet carrier (13). The transmission output shaft thus rotates with reduced transmission input speed in the direction of rotation of the engine.

Power flow in 4th gear, function - GF27.10-P-3014GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 204.0, 216, 221, 251.0/1 up to Model Year 8

Scheme 240

The Ravigneaux gear set consists of the following components

1. Short planet gears
2. Long planet gears
3. Small internal-geared wheel
4. Dual planet carrier
5. Sun gear (7)
6. Large internal-geared wheel

The front single planetary gear set consists of the following components

1. Planetary gears (52)
2. Internal-geared wheel (12)
3. Planet carrier (13)
4. Sun gear (14)

The rear single planetary gear set consists of the following components

1. Planetary gears (51)
2. Internal-geared wheel (9)
3. Planet carrier (10)
4. Sun gear (11)

Power flow in 4th gear, function

The following multi-disk brakes and multi-disk clutches are engaged

1. Multidisk brake B2
2. Multidisk clutch K1
3. Multidisk clutch K2

Ravigneaux gear set

Due to the engaged multidisk clutch K1 the components of the Ravigneaux gear set are locked together and pass on the transmission input torque and transmission input speed unchanged to the ring gear (9).

Single rear planetary gear system

Due to the engaged multidisk clutch K2 the rotational speeds of ring gear (9) and ring gear (12) are the same. As a result the single rear planetary gear system is locked and not actively involved in the gear ratio.

Single front planetary gear system

Due to the engaged multidisk clutch K2 the ring gear (12) is driven at transmission input speed. The planetary gears (52) roll on the stalled sun gear (14) and transfer the increased torque and reduced rotational speed to the transmission output shaft via the planet carrier (13). The transmission output shaft thus rotates with reduced transmission input speed in the direction of rotation of the engine.

Power flow in 5th gear, function - GF27.10-P-3015AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of Model Year 09/Modification year 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of Model Year 09/Modification Year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of Model Year 09/Modification year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of Model Year 09/Modification year 08

Scheme 241

Function requirements for power flow in 5th gear, general

1. Circuit 87 ON
2. Engine running

Power flow in 5th gear, general

The following multi-disk clutches are engaged

1. Multidisk clutch K1 (46)
2. Multidisk clutch K2 (47)
3. Multidisk clutch K3 (48)

In 5th gear, power flows from the transmission input shaft through the blocked Ravigneaux gear set and blocked front single planetary gear set to the transmission output shaft. This rotates at the transmission input speed in the direction of rotation of the engine.

Power flow in 5th gear, function - GF27.10-P-3015GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 204.0, 216, 221, 251.0/1 up to Model Year 8

Scheme 242

The Ravigneaux gear set consists of the following components

1. Short planet gears
2. Long planet gears
3. Small internal-geared wheel
4. Dual planet carrier
5. Sun gear (7)
6. Large internal-geared wheel

The front single planetary gear set consists of the following components

1. Planetary gears (52)
2. Internal-geared wheel (12)
3. Planet carrier (13)
4. Sun gear (14)

The rear single planetary gear set consists of the following components

1. Planetary gears (51)
2. Internal-geared wheel (9)
3. Planet carrier (10)
4. Sun gear (11)

Power flow in 5th gear, function

The following multi-disk clutches are engaged

1. Multi-disk clutch K1
2. Multi-disk clutch K2
3. Multi-disk clutch K3

The power flow runs from the transmission input shaft of the automatic transmission (AT) via the blocked Ravigneaux gear set and the blocked front single planetary gear set to the output. The transmission output shaft rotates at the transmission input speed in the direction of rotation of the engine.

Function of power flow in reverse gear Function of program selection "S" - GF27.10-P-3017GZ

TRANSMISSION 722.9 in MODEL 164.120/122/128/175/186 with CODE (430) Offroad package except CODE (494) USA version up to Model Year 8

TRANSMISSION 722.9 in MODEL 164.177,204.0, 216, 221, 251.0/1 up to Model Year 8

TRANSMISSION 722.9 in MODEL 164.822/828/871/886 except CODE (494) USA version up to Model Year 8

Scheme 243

The Ravigneaux gear set consists of the following components

1. Short planet gears
2. Long planet gears
3. Small internal-geared wheel
4. Dual planet carrier
5. Sun gear (7)
6. Large internal-geared wheel

The front single planetary gear set consists of the following components

1. Planetary gears (52)
2. Internal-geared wheel (12)
3. Planet carrier (13)
4. Sun gear (14)

The rear single planetary gear set consists of the following components

1. Planetary gears (51)
2. Internal-geared wheel (9)
3. Planet carrier (10)
4. Sun gear (11)

Power flow in reverse gear, program selection "S", function

The following multi-disk brakes and multi-disk clutches are engaged

1. Multi-disk brake BR
2. Multidisk brake B1
3. Multidisk clutch K3

Ravigneaux gear set

The small ring gear is driven via the transmission input shaft. The long planetary gears roll over the stalled sun gear (7) and transmit the increased torque and reduced rotational speed to the dual planet carrier.

Single rear planetary gear system

The ring gear (9) rotates at the same speed due to the mechanical connection to the dual planet carrier. The planetary gears (51) roll on the sun gear (11). Due to the stalled planet carrier (10), the rotational direction of the sun gear (11) reverses.

Single front planetary gear system

There is a connection between sun gear (14) and sun gear (11) via the engaged multidisk clutch K3. As a result sun gear (14) rotates at the same speed and direction of rotation as sun gear (11) and drives the planetary gears (52). The increased torque and reduced rotational speed as a result are transmitted via the planet carrier (13) to the transmission output shaft. The transmission output shaft thus rotates at reduced transmission input speed opposite to the direction of the engine.

Power flow in 6th gear, function - GF27.10-P-3021AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of Model Year 09/Modification year 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of Model Year 09/Modification Year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of Model Year 09/Modification year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of Model Year 09/Modification year 08

Scheme 244

Function requirements for power flow in 6th gear, general

1. Circuit 87 ON
2. Engine running

Power flow in 6th gear, general

The following multi-disk brakes and multi-disk clutches are engaged

1. Multidisk brake B1 (42)
2. Multidisk clutch K2 (47)
3. Multidisk clutch K3 (48)

In 6th gear, the power flows through the following gear sets

1. Ravigneaux gear set
2. Rear single planetary gear set
3. Front single planetary gear set

Ravigneaux gear set

The small ring gear (5) is driven via the transmission input shaft. The long planetary gears (50) roll over the stalled sun gear (7) and transmit the increased torque and reduced rotational speed as a result to the dual planet carrier (6).

Rear single planetary gear set

The ring gear (9) rotates at the same speed due to the mechanical connection to the dual planet carrier (6). The planetary gears (51) transmit the rotary motion to the sun gear (11). Sun gear (11) passes on the rotational speed to sun gear (14) via the closed multi-disk clutch K3 (48).

Front single planetary gear set

The transmission input torque and transmission input speed are transmitted to the ring gear (12) by the closed multi-disk clutch K2 (47). The speed difference between the sun gear (14) and ring gear (12) results in a speed increase and torque reduction. These are passed on via the planet carrier (13) to the transmission output shaft. The transmission output shaft thus rotates with reduced transmission input speed in the direction of rotation of the engine.

Power flow in 6th gear, function - GF27.10-P-3021GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 204.0, 216, 221, 251.0/1 up to Model Year 8

Scheme 245

The Ravigneaux gear set consists of the following components

1. Short planet gears
2. Long planet gears
3. Small internal-geared wheel
4. Dual planet carrier
5. Sun gear (7)
6. Large internal-geared wheel

The front single planetary gear set consists of the following components

1. Planetary gears (52)
2. Internal-geared wheel (12)
3. Planet carrier (13)
4. Sun gear (14)

The rear single planetary gear set consists of the following components

1. Planetary gears (51)
2. Internal-geared wheel (9)
3. Planet carrier (10)
4. Sun gear (11)

Power flow in 6th gear, function

The following multi-disk brakes and multi-disk clutches are engaged

1. Multidisk brake B1
2. Multidisk clutch K2
3. Multidisk clutch K3

Ravigneaux gear set

The small ring gear is driven via the transmission input shaft. The long planetary gears roll over the stalled sun gear (7) and transmit the increased torque and reduced rotational speed to the dual planet carrier.

Single rear planetary gear system

The ring gear (9) rotates at the same speed due to the mechanical connection to the dual planet carrier. The planetary gears (51) transmit the rotary motion to the sun gear (11). Sun gear (11) passes on the rotational speed to sun gear (14) via the engaged multidisk clutch K3.

Single front planetary gear system

The transmission input torque and transmission input speed are transmitted to the ring gear (12) by the engaged multidisk clutch K2. The speed difference between the sun gear (14) and ring gear (12) results in a speed increase and torque reduction. These are passed on via the planet carrier (13) to the transmission output shaft. The transmission output shaft thus rotates with reduced transmission input speed in the direction of rotation of the engine.

Oil level control, function - GF27.10-P-3024GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 204.0, 216, 221, 251.0/1 up to Model Year 8

The oil level regulating system seals the openings between the oil gallery and gear set chamber so that the rotating gear sets do not churn in the oil as the oil level rises.

The power losses occurring are reduced and oil is prevented from being thrown out of the transmission housing at high temperatures.

Power flow in reverse gear, program selection "C", function - GF27.10-P-3025SX

TRANSMISSION 722.9 in MODEL 164.177,204.0, 216, 221, 251.0/1 up to Model Year 8

Scheme 246

The Ravigneaux gear set consists of the following components

1. Short planet gears
2. Long planet gears
3. Small internal-geared wheel
4. Dual planet carrier
5. Sun gear (7)
6. Large internal-geared wheel

The front single planetary gear set consists of the following components

1. Planetary gears (52)
2. Internal-geared wheel (12)
3. Planet carrier (13)
4. Sun gear (14)

The rear single planetary gear set consists of the following components

1. Planetary gears (51)
2. Internal-geared wheel (9)
3. Planet carrier (10)
4. Sun gear (11)

Power flow in reverse gear, program selection "C", function

The following multi-disk brakes and multi-disk clutches are engaged

1. Multi-disk brake BR
2. Multiple-disk brake B3
3. Multi-disk clutch K3

Ravigneaux gear set

The small ring gear is driven via the transmission input shaft. The long planetary gears drive the short planetary gears which roll in the large stalled ring gear. The resulting increased torque and resulting decreased rotational speed are transmitted to the dual planet carrier.

Single rear planetary gear system

The ring gear (9) rotates at the same rotational speed due to the mechanical connection to the dual planet carrier. The planet gears (51) roll on the sun gear (11). The stalled planet carrier (10) results in the sun gear (11) reversing its direction of rotation (10).

Single front planetary gear system

Sun gear (14) is connected to sun gear (11) via the engaged multi-disk clutch K3 As a result the sun gear (14) rotates at the same rotational speed and direction of rotation as sun gear (11) and drives the planetary gears (52). The increased torque and reduced rotational speed as a result are transmitted via the planet carrier (13) to the transmission output shaft. The transmission output shaft thus rotates at reduced transmission input speed opposite to the direction of rotation of the engine.

Power flow in 7th gear, function - GF27.10-P-3026AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of Model Year 09/Modification year 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of Model Year 09/Modification Year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of Model Year 09/Modification year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of Model Year 09/Modification year 08

Scheme 247

Function requirements for power flow in 7th gear, general

1. Circuit 87 ON
2. Engine running

Power flow in 7th gear, general

The following multi-disk brakes and multi-disk clutches are engaged

1. Multidisk brake B3 (45)
2. Multidisk clutch K2 (47)
3. Multidisk clutch K3 (48)

In 7th gear, the power flows through the following gear sets

1. Ravigneaux gear set
2. Rear single planetary gear set
3. Front single planetary gear set

Ravigneaux gear set

The small ring gear (5) is driven via the transmission input shaft. The long planetary gears (50) drive the short planetary gears (49) which roll in the stalled large ring gear (8). The increased torque and reduced rotational speed as a result are transmitted to the dual planet carrier (6).

Rear single planetary gear set

The ring gear (9) rotates at the same speed due to the mechanical connection to the dual planet carrier (6). The planetary gears (51) transmit the rotary motion to the sun gear (11). Sun gear (11) passes on the rotational speed to sun gear (14) via the closed multi-disk clutch K3 (48).

Front single planetary gear set

The transmission input torque and transmission input speed are transmitted to the ring gear (12) by the closed multi-disk clutch K2 (47). The speed difference between the sun gear (14) and ring gear (12) results in a speed increase and torque reduction. These are passed on via the planet carrier (13) to the transmission output shaft. The transmission output shaft thus rotates with reduced transmission input speed in the direction of rotation of the engine.

Power flow in 7th gear, function - GF27.10-P-3026GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 204.0, 216, 221, 251.0/1 up to Model Year 8

Scheme 248

The Ravigneaux gear set consists of the following components

1. Short planet gears
2. Long planet gears
3. Small internal-geared wheel
4. Dual planet carrier
5. Sun gear (7)
6. Large internal-geared wheel

The front single planetary gear set consists of the following components

1. Planetary gears (52)
2. Internal-geared wheel (12)
3. Planet carrier (13)
4. Sun gear (14)

The rear single planetary gear set consists of the following components

1. Planetary gears (51)
2. Internal-geared wheel (9)
3. Planet carrier (10)
4. Sun gear (11)

Power flow in 7th gear, function

The following multi-disk brakes and multi-disk clutches are engaged

1. Multiple-disk brake B3
2. Multi-disk clutch K2
3. Multi-disk clutch K3

Ravigneaux gear set

The small ring gear is driven via the transmission input shaft. The long planetary gears drive the short planetary gears which roll in the large stalled ring gear. The resulting increased torque and resulting decreased rotational speed are transmitted to the dual planet carrier.

Single rear planetary gear system

The ring gear (9) rotates at the same rotational speed due to the mechanical connection to the dual planet carrier. The planetary gears (51) transmit the rotary motion to the sun gear (11). The sun gear (11) passes on the rotational speed to the sun gear (14) via the closed multi-disk clutch K3.

Single front planetary gear system

The closed multi-disk clutch K2 means that the transmission input torque and transmission input speed are transmitted to the ring gear (12). There is an increased rotation speed and a reduced torque due to the speed difference between the sun gear (14) and ring gear (12). These are passed on via the planet carrier (13) to the transmission output shaft. The transmission output shaft thus rotates with reduced transmission input speed in the direction of rotation of the engine.

Locking of gear selector switch position "P" function - GF27.10-P-3027GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 216, 221, 251.0/1 up to Model Year 8

Locking of the gear selection position "P" is a subfunction of the function Key-P. The selector lever is locked electronically. The gear selector switch position "P" cannot be exited, if no enable is granted by the drive authorization system stage 3 (DAS 3), the brake is not operated or the intelligent servo module for DIRECT SELECT (A80) is not supplied with voltage.

Key-P function - GF27.10-P-3028AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of Model Year 09/Modification year 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of Model Year 09/Modification Year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of Model Year 09/Modification year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of Model Year 09/Modification year 08

Key-P function requirements, general

1. Circuit 15 ON
2. Brake pedal operated
3. Vehicle speed > 8 km/h

Key-P, general

The designation Key-P comprises all the functions which in addition to the parking brake serve to secure the vehicle to prevent it from rolling away unintentionally.

Key-P function sequence

The function sequence is subdivided into the following steps

1. Park pawl function sequence
2. Ignition lock function sequence
3. Selector lever position "P" lock function sequence
4. Emergency-P function sequence (see document, Emergency-P function)

Park pawl function sequence

The park pawl only permits shifting out of selector lever position "P" through the gear selector switch DIRECT SELECT (S16/13) when the transmitter key (A8/1) is turned into position "circuit 15 ON" and the brake pedal is operated.

In order to ensure that after parking the vehicle the selector lever is automatically shifted into selector lever position "P" by the intelligent servo module for DIRECT SELECT (A80), in this position the transmitter key can only be turned towards "0" and removed from the EIS [EZS] control unit (N73). The vehicle is secured mechanically by blocking the park pawl gear in the transmission.

With CODE (889) Keyless Go

On vehicles with Keyless Go, selector lever position "P" is engaged when the driver door is opened after the vehicle is parked.

Ignition lock function sequence

The EIS [EZS] control unit locks the transmitter key mechanically at a vehicle speed >8 km/h.

It prevents the transmitter key from being removed because automatic engagement of selector lever position "P" cannot be performed by the intelligent servo module.

The transmitter key can be removed as long as the vehicle speed remains below the speed threshold and selector lever position "P" or "N" is automatically engaged by the intelligent servo module.

Selector lever position "P" lock function sequence

The selector lever remains locked in position "P" if the following conditions are not met

1. No power supply from intelligent servo module
2. No enable signal from the drive authorization system (DAS 3)
3. Brake pedal not actuated

electrical function schematic Key-P Model 164 PE27.19-P-2058-97MAA Model 251 PE27.19-P-2058-97RAA Emergency-P function GF27.10-P-3029AHZ Intelligent servo module for DIRECT SELECT, component description A80 GF27.19-P-4020AHZ

Key-P function - GF27.10-P-3028GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 216, 221, 251.0/1 up to Model Year 8

Key-P is used to summarize the functions which serve to prevent the vehicle from inadvertently rolling away in addition the parking brake. These include locking gear selector switch position "P", locking the ignition switch as well as the park pawl in the transmission. The function Key-P only permits switching out of gear selector switch position "P", if the transmitter key (A8/1) has been turned into position "circuit 15 ON" and the brake pedal is pressed.

Model 221 up to 31.8.06, model 164 and model 251 up to 31.5.07

In order to ensure that with "terminal 15 OFF" and a parked vehicle gear selector switch "P" is shifted, gear selector switch position "P" is automatically shifted by the intelligent servo module for DIRECT SELECT (A80), as soon as the transmitter key is removed from the EIS [EZS] control unit (N73). The vehicle is secured mechanically by blocking the park pawl gear.

On vehicles with code (889) Keyless Go the system also switches into gear selector position "P", if the driver door is opened after parking the vehicle

Model 216, model 221 as of 1.9.06, model 164 and model 251 as of 1.6.07

The gear selector switch position "P" is automatically shifted by the Intelligent servo module for DIRECT SELECT for the following function requirements

1. Circuit 15 OFF
2. Driver door OPEN

The vehicle is secured mechanically by blocking the park pawl gear. If it is not possible to implement the Key-P function, for example because of undervoltage in the on-board electrical system, then the emergency-P function is activated.

Emergency-P function - GF27.10-P-3029AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of model year 2009/CY 08 model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of model year 2009/CY08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of model year 2009/modification year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of model year 2009/modification year 08

Function requirements for Emergency-P, general

1. Emergency motor supply voltage

Emergency-P, general

In emergencies, if for example undervoltage prevails in the on-board electrical system or the communication with the intelligent servo module for DIRECT SELECT (A80) is faulty, the emergency motor in the intelligent servo module for DIRECT SELECT is supplied with voltage by the additional battery via the EIS [EZS] control unit (N73) and thus triggers the emergency P function G1/7

As of 1.9.08 with the eccentric shaft driven by the emergency motor the gearwheel drive is replaced by a belt drive

Emergency-P function sequence

The function sequence is subdivided into the following steps

1. Start position function sequence
2. Intermediate position function sequence
3. End position function sequence
4. Function sequence cancellation

Start position function sequence

Start position, shown up to 31.8.08

Scheme 249

By means of the additional battery, the emergency motor is supplied with voltage via the EZS control unit in an emergency, e.g. undervoltage in the on-board electrical system, and turns the eccentric shaft.

Intermediate position function sequence

Intermediate position, shown up to 31.8.08

Scheme 250

The rotating eccentric shaft presses down onto the release studs of the left carriage half. This in turn causes the mechanical connection between the left and right carriage halves to be broken.

End position function sequence

End position, shown up to 31.8.08

Scheme 251

The pre-compressed coil spring pushes the two carriage halves apart. The right carriage half slides along the threaded spindle to the right and pushes the range selector lever to position "P". The eccentric shaft continues to rotate, until the emergency motor is no longer actuated. The actual position of the eccentric shaft is recorded by the eccentric shaft position sensor.

Function sequence cancellation

If undervoltage is no longer present in the on-board electrical system, the Emergency-P function is deactivated and the intelligent servo module for DIRECT SELECT reverts to its normal operating condition.

The main motor drives the threaded spindle by way of the drive pinion gears. The left carriage half runs on to the right carriage half, the coil spring is pre-compressed again and the mechanical connection made again.

The Emergency-P function cannot be overridden manually

Emergency-P function - GF27.10-P-3029GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 251.0/1 up to Model Year 8

The Key-P function can still be activated in emergencies e.g. if there is undervoltage in the on-board electrical system or communication to the intelligent servo module for DIRECT SELECT (A80) is interrupted.

In these cases, an emergency motor in the intelligent servo module for DIRECT SELECT is supplied with voltage via the EIS [EZS] control unit (N73) by an additional battery (G1/7), triggering the Emergency-P function.

If undervoltage is no longer present in the on-board electrical system, the Emergency-P function is deactivated and the intelligent servo module for DIRECT SELECT reverts to its normal operating condition.

The Emergency-P function cannot be overridden manually.

The additional battery is located in the front passenger footwell near battery (G1)

Power flow in reverse gear, transmission mode "S", function - GF27.10-P-3030AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of Model Year 09/Modification year 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of Model Year 09/Modification Year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of Model Year 09/Modification year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of Model Year 09/Modification year 08

Scheme 252

Function requirements for power flow in reverse gear in transmission mode "S", general

1. Circuit 87 ON
2. Engine running

Power flow in reverse gear, transmission mode "S", general

The following multi-disk brakes and multi-disk clutches are engaged

1. Multidisk brake BR (41)
2. Multidisk brake B1 (42)
3. Multidisk clutch K3 (48)

In reverse gear with

transmission mode "S", the power flows through the following gear sets

1. Ravigneaux gear set
2. Rear single planetary gear set
3. Front single planetary gear set

Ravigneaux gear set

The small ring gear (5) is driven via the transmission input shaft. The long planetary gears (50) roll over the stalled sun gear (7) and transmit the increased torque and reduced rotational speed as a result to the dual planet carrier (6).

Rear single planetary gear set

The ring gear (9) rotates at the same speed due to the mechanical connection to the dual planet carrier (6). The planetary gears (51) roll on the sun gear (11). Through the stalled planet carrier (10) a reversal of direction of rotation occurs at the sun gear (11).

Front single planetary gear set

There is a connection between the sun gear (14) and sun gear (11) via the engaged multi-disk clutch K3 (48). As a result sun gear (14) rotates at the same speed and direction of rotation as sun gear (11) and drives the planetary gears (52). The increased torque and reduced rotational speed as a result are transmitted via the planet carrier (13) to the transmission output shaft. The transmission output shaft thus rotates at reduced transmission input speed opposite to the direction of the engine.

Document title Power flow in reverse gear, transmission mode "C", function

Document number gf2710p3031ahz

Power flow in reverse gear, transmission mode "C", function - GF27.10-P-3031AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of Model Year 09/Modification year 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of Model Year 09/Modification Year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of Model Year 09/Modification year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of Model Year 09/Modification year 08

Scheme 253

Function requirements for power flow in reverse gear in transmission mode "C", general

1. Circuit 87 ON
2. Engine running

Power flow in reverse gear, transmission mode "C", general

The following multi-disk brakes and multi-disk clutches are engaged

1. Multidisk brake BR (41)
2. Multidisk brake B3 (45)
3. Multidisk clutch K3 (48)

In reverse gear with

transmission mode "C", the power flows through the following gear sets

1. Ravigneaux gear set
2. Rear single planetary gear set
3. Front single planetary gear set

Ravigneaux gear set

The small ring gear (5) is driven via the transmission input shaft. The long planetary gears (50) drive the short planetary gears (49) which roll in the stalled large ring gear (8). The increased torque and reduced rotational speed as a result are transmitted to the dual planet carrier (6).

Rear single planetary gear set

The ring gear (9) rotates at the same speed due to the mechanical connection to the dual planet carrier (6). The planetary gears (51) roll on the sun gear (11). Through the stalled planet carrier (10) a reversal of direction of rotation occurs at the sun gear (11).

Front single planetary gear set

There is a connection between the sun gear (14) and sun gear (11) via the engaged multi-disk clutch K3 (48). As a result sun gear (14) rotates at the same speed and direction of rotation as sun gear (11) and drives the planetary gears (52). The increased torque and reduced rotational speed as a result are transmitted via the planet carrier (13) to the transmission output shaft. The transmission output shaft thus rotates at reduced transmission input speed opposite to the direction of the engine.

Transmission oil cooling, function - GF27.55-P-2000AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of Model Year 09/Modification year 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of Model Year 09/Modification Year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of Model Year 09/Modification year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of Model Year 09/Modification year 08

Cooling circuit

Scheme 254

Function requirements for transmission oil cooling, general

1. Circuit 87 ON
2. Circuit 61 (engine running)

Transmission oil cooling, general

Transmission oil cooling lowers the temperature of the transmission oil and thus prevents overheating damage in the transmission.

Function sequence of transmission oil cooling

The transmission oil is drawn out of the transmission oil pan by a mechanical pump in the transmission and pumped via the feed to the transmission cooler (which is integrated in the engine radiator). The transmission oil then flows through the return line back to the transmission.

Gear shift, function - GF27.60-P-2000AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of Model Year 09/Modification year 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of Model Year 09/Modification Year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of Model Year 09/Modification year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of Model Year 09/Modification year 08

Function requirements for shift operation, general

1. Circuit 87 ON
2. Circuit 61 (engine running)
3. Engine speed from CDI control unit (N3/9) or ME-SFI control unit (N3/10)
4. Transmission not in limp-home mode
5. Engine compartment CAN (CAN-C) signals

Shift operation, general

The electric controller unit (VGS) (Y3/8) converts the electrical signals coming from the fully integrated transmission control unit (VGS) (Y3/8n4) into hydraulic signals. The selector lever positions "P, R, N, D" from the DIRECT SELECT gear selector switch (S16/13) are transferred to the engine compartment CAN (CAN C) by the steering column tube module (N80).

The CDI control unit or ME-SFI control unit transfers the information on the engine compartment CAN. Taking various information into account, the intelligent servo module for DIRECT SELECT (A80) transfers the selector lever positions to the fully integrated transmission control unit (VGS). The intelligent servo module changes the position of the selector range lever, which is transmitted to the selection range sensor (VGS) (Y3/8s1).

The shift range is displayed in the instrument cluster (A1).

Although the shift range can be changed in the forward gears while driving, the fully integrated transmission control unit (VGS) prevents a shift operation if the engine speed is too high or too low.

Shift operation, function sequence

The function sequence is subdivided into the following steps

1. Function sequence for upshift and downshift
2. Function sequence for 1 to 2 shift

Function sequence for upshift and downshift

In transmission modes Sport "S" and Comfort "C" the driver can select the following functions by operating the steering wheel gear shifter MINUS (S110/1) and the steering wheel gear shifter PLUS (S111/1)

One press toward "-" activates the gear limitation function (a downshift is made to the gear that lies exactly one below the currently selected one if the engine speed allows).

Pressing and holding towards "-" selects the "Shift to optimal gear" function (the gear which allows the best vehicle acceleration is selected).

One press toward "+" with the gear limitation function selected increases gearshift limitation by one gear (e.g. from 3 to 4).

One press toward direction "+" in gear range "D" sends an upshift request to the transmission (the transmission shifts up depending on the driving situation).

Pressing and holding toward "+" cancels the gear limitation function completely (gearshift to "D").

In transmission mode Comfort "C" in comparison with the transmission mode Sport "S" a shorter shift range (shifting at low engine speed) and therefore a lower drive torque is available. This enables a gentler start-off as the gears are not driven to the limit.

In transmission mode Manual "M" (except code (494) USA version), the individual gears "1, 2, 3, 4, 5, 6, 7" can be shifted directly using the MINUS and PLUS steering wheel gear shifter.

The reverse gear, park position and neutral position can only be engaged using the DIRECT SELECT gear selector switch.

Manual transmission mode

Transmission mode Manual "M" is no longer active after ignition "OFF" --> "ON". The transmission always starts in the last selected transmission mode. ("S" or "C").

Function sequence for 1 to 2 shift

Multidisk brake B2, multidisk brake B3 and multidisk clutch K3 are engaged in 1st gear. When shifting from 1st gear to 2nd gear, multidisk brake B3 is disengaged and multidisk brake B1 is engaged. The shift operation is started by the fully integrated transmission control unit (VGS). Here, the multidisk brake B1 is filled and the pressure in multidisk brake B1 is increased continuously. Simultaneously the pressure in multi-disk brake B3 is reduced. This involves a flowing transition. After upshifting, RPM is adapted to the RPM level of the next highest gear. (multiplication phase).

This speed adjustment is achieved by the pressure in the multi-disk brake B1 being increased and, if necessary, engine torque being reduced via the CDI control unit or ME-SFI control unit.

A forced downshift occurs at excessively low RPM and a forced upshift occurs at an excessively high RPM.

When the vehicle is stationary the transmission automatically shifts into 1st gear. It is possible to start off both in 1st or 2nd gear.

electrical function schematic Shift mechanism Model 164 PE27.19-P-2057-97MAA Model 251 PE27.19-P-2057-97RAA Emergency default mode, function GF27.60-P-3012AHZ Engage gear range, function GF27.60-P-3009AHZ Torque converter lockup clutch control, function GF27.20-P-3002AHZ Torque converter lockup clutch control pressure, function GF27.60-P-3019AHZ Working/lubrication/shift pressure, function GF27.60-P-3024AHZ Control valve pressure, function GF27.60-P-3017AHZ

TRANSMISSION 722.9 in MODEL 164.177,204.0, 216, 221, 251.0/1 up to Model Year 8

Scheme 255

The Ravigneaux gear set consists of the following components

1. Short planet gears
2. Long planet gears
3. Small internal-geared wheel
4. Dual planet carrier
5. Sun gear (7)
6. Large internal-geared wheel

The front single planetary gear set consists of the following components

1. Planetary gears (52)
2. Internal-geared wheel (12)
3. Planet carrier (13)
4. Sun gear (14)

The rear single planetary gear set consists of the following components

1. Planetary gears (51)
2. Internal-geared wheel (9)
3. Planet carrier (10)
4. Sun gear (11)

Power flow in reverse gear, program selection "C", function

The following multi-disk brakes and multi-disk clutches are engaged

1. Multi-disk brake BR
2. Multiple-disk brake B3
3. Multi-disk clutch K3

Ravigneaux gear set

The small ring gear is driven via the transmission input shaft. The long planetary gears drive the short planetary gears which roll in the large stalled ring gear. The resulting increased torque and resulting decreased rotational speed are transmitted to the dual planet carrier.

Single rear planetary gear system

The ring gear (9) rotates at the same rotational speed due to the mechanical connection to the dual planet carrier. The planet gears (51) roll on the sun gear (11). The stalled planet carrier (10) results in the sun gear (11) reversing its direction of rotation (10).

Single front planetary gear system

Sun gear (14) is connected to sun gear (11) via the engaged multi-disk clutch K3 As a result the sun gear (14) rotates at the same rotational speed and direction of rotation as sun gear (11) and drives the planetary gears (52). The increased torque and reduced rotational speed as a result are transmitted via the planet carrier (13) to the transmission output shaft. The transmission output shaft thus rotates at reduced transmission input speed opposite to the direction of rotation of the engine.

Transmission control, function - GF27.60-P-2002AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of Model Year 09/Modification year 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of Model Year 09/Modification Year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of Model Year 09/Modification year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of Model Year 09/Modification year 08

Function requirements for transmission control, general

1. Circuit 87 ON
2. Function check performed on fully integrated transmission control unit (VGS) (Y3/8n4)

Transmission control, general

The transmission control system electronically actuates the actuators (control solenoid valves). The valves are positioned on the electric controller unit (VGS). This implements the hydraulic functions. The function of the electric controller unit (VGS) is primarily to evaluate various input signals that are relevant to transmission operation. Based on this, eight electromechanical hydraulic valves are actuated which determine the gear ratio of the transmission (gear selection), the working pressure and the torque converter lockup.

Transmission control function sequence

The function sequence is subdivided into the following steps

1. Basic shift program function sequence
2. Electronic and hydraulic transmission control function sequence
3. Kick-down function sequence
4. Limp-home mode function sequence

Basic shift program function sequence

The basic shift program includes upshift and downshift characteristics for all 7 gears, designed for

1. Empty vehicle
2. Operating temperature
3. Level road
4. Sea level

The basic shift program can be influenced by the driver through the transmission mode switch (N72/1s32).

The shift programs are adapted by offsetting the characteristics, depending on

1. Vehicle load
2. Change in driving resistance
3. Accelerator pedal movement

The fully integrated transmission control (VGS) control unit (Y3/8n4) monitors and shifts depending on

1. Vehicle speed
2. Selector lever position
3. Accelerator pedal position
4. Transmission mode selection
5. Selected gear in transmission mode Manual "M" (except code (494) USA version)
6. Signals on engine compartment CAN (CAN-C)

Slow accelerator release

1. Undesired downshifts in the upper vehicle speed range are prevented

Rapid accelerator release

1. Upshifting to the next gear up is prevented and only permitted again when the vehicle accelerates slowly

Electronic and hydraulic transmission control function sequence

While the electronic transmission control takes over the gear selection and adaptation of pressures to the torque to be transmitted, the power supply of the transmission is controlled via the hydraulic elements of the electric controller unit (VGS). The oil supply to the hydraulic elements, such as the hydrodynamic torque converter, the shift elements and the hydraulic transmission control, is provided by way of an oil pump connected to the torque converter. The transmission control system makes possible a precise adaptation of pressures to the respective operating conditions and to the engine output during the gearshift phase, resulting in a significant improvement in shift quality.

It is possible to reach the engine RPM limit in the individual gears using full throttle and kickdown.

The transmission control system prevents impermissibly high engine speeds with a downshift lock-out device. Furthermore, the transmission control system offers the advantage of a flexible adaptation to various vehicle and engine versions.

Kick-down function sequence

The driver's wish for maximum acceleration is met by the kickdown function.

The kickdown function is activated as of a pedal travel > 90 %.

The "Kick-down" signal is transferred to the fully integrated transmission control unit (VGS) by the CDI control unit (N3/9) or ME-SFI [ME] control unit (N3/10) via the engine compartment CAN. Based on this information the fully integrated transmission control (VGS) control unit actuates the control solenoid valves so that the upshifts and downshifts take place at higher engine speeds in order to achieve maximum performance.

Limp-home mode function sequence

If the signals are implausible, the transmission control system is only partially operational and switches to the programmed emergency performance map.

The driver can engage the desired gear ranges "P, R, N, D" with the DIRECT SELECT gear selector switch (S16/13).

The driver can choose been forward and reverse travel, engage the park pawl or interrupt the power flow between torque converter and transmission in the neutral position.

Function schematic of electrical system of electronic transmission control (ETC) Model 164 PE27.19-P-2050-97MAB Model 251 PE27.19-P-2050-97RAB Fully integrated transmission control unit, component description Y3/8n4 GF27.60-P-5165AHZ

Transmission control, function - GF27.60-P-2002GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 251.0/1 up to Model Year 8

The transmission control is divided into the electronic and hydraulic transmission control functions. While the electronic transmission control takes over the gear selection and adaptation of pressures to the torque to be transmitted, the power supply of the transmission is controlled via the hydraulic elements of the electrohydraulic controller unit. The oil supply to the hydraulic elements, such as the hydrodynamic torque converter, the shift elements and the hydraulic transmission control, is provided by way of an oil pump connected to the torque converter. The fully integrated transmission control (VGS) makes possible precise adaptation of pressures to the respective operating conditions and to the engine output during the shift phase which results in a significant increase in shift quality. The engine speed limit can be reached in the individual gears at full throttle and kickdown.

The shifting range can be altered in the forward gears while driving. The fully integrated transmission control (VGS) prevents the driver revving the engine too high, however, by means of a downshift safeguard. Furthermore, the fully integrated transmission control (VGS) provides the advantage of flexible adaptation to various vehicle and engine versions.

Model 164.120/122/128/175/186 except code (430) Offroad package

The driver can activate or deactivate the Offroad program. These also provide different gear ratios for reverse gear.

Model 164.120/122/128/175/186 with code (430) Offroad package, model 164.822/828/871/886

Reverse gear "R" with the ratio used in the transmission mode "S" is available to the driver.

Model 251.022/065/075/122/165/175

Transmission modes "C" and "S" are available to the driver. These also provide different gear ratios for reverse gear.

Model 164.177, 251.077/177

The driver can choose between 3 transmission modes "S" (sport program), "C" (comfort program) and "M" (manual program). These also provide different gear ratios for reverse gear.

The fully integrated transmission control (VGS) control unit (Y3/8n4) monitors and shifts depending on

1. Vehicle speed
2. Gear selector switch position
3. Accelerator pedal position
4. Offroad program activated or deactivated, model 164.120/122/128/175/186 except code (430) Offroad package
5. Transmission mode, model 164.120/122/128/175/186 with code (430) Offroad package, model 164.177, model 164.822/828/871/886, model 251.022/065/075/077/122/165/175/177
6. Selected gear, with program selection "M", model 164.177, 251.077/177
7. The state of the transmission
8. Signals on the Controller Area Network bus class C (engine compartment) (CAN-C)

Engage gear range, function - GF27.60-P-3009AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of model year 2009/CY 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of model year 2009/CY 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of model year 2009/CY 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of model year 2009/CY 08

Function requirements for gear range engagement, general

1. Circuit 87 ON
2. Circuit 61 ON

Gear range engagement, general

Each gear change is triggered by the fully integrated transmission control (VGS). In the process one component group is assigned to each shift operation.

One component group consists of the respective control solenoid valve, regulating valve involved, shift valve responsible and the required multidisk brake or multidisk clutch.

The pressure in the multidisk brake or multidisk clutch to be engaged is increased constantly while at the same time the pressure in the multidisk brake or multidisk clutch to be disengaged is reduced. The process is a smooth transition and the components affected are actuated directly. This makes it possible to downshift, even through several gears.

Gear range engagement, function sequence

Shifting "N" to "D" (1st gear)

In position "N" of the DIRECT SELECT gear selector switch (S16/13), multidisk brake B3 and multidisk clutch K3 are engaged. When the intelligent servo module for DIRECT SELECT (A80) shifts from position "N" to position "D", the feed to multidisk brake B2 is enabled by the selector valve. The fully integrated transmission control unit (VGS) (Y3/8n4) actuates brake control solenoid valve B2 (VGS) (Y3/8y6) and multidisk brake B2 is filled with oil.

By the RPM difference (actual slip) between the engine speed and turbine speed the fully integrated transmission control unit (VGS) detects whether the multidisk brake B2 is full.

The brake control solenoid valve B2 (VGS) actuates the regulating valve B2 and BR which converts the adjacent working pressure into shift pressure and passes it on to the multidisk brake B2

In the fully integrated transmission control unit (VGS), the required slip (specified slip) is stored for the respective gear. Depending on the specified slip, the control pressure on regulating valves B2 and BR is changed via brake control solenoid valve B2 (VGS).

The pressure in multidisk brake B2 is changed until the specified slip stored in the fully integrated transmission control unit (VGS) is reached.

The shift pressure produced by the regulating valve B2 and BR depends on the geometry of the regulating valve B2 and BR

"No power" function sequence in gear range "D" on model 164 and model 251 in combination with engine 642 as of 5.1.2009

Function requirements

1. The vehicle speed v = approx. 15 km/h must be exceeded once after engaging the selector switch position "D".
2. The "no power" function sequence in gear range "D" is activated in the DIRECT SELECT gear selector switch position "D" if the following conditions are met: The driver has braked the vehicle to a standstill Transmission temperature in range from 10°C to 110°C Coolant temperature in the range from 0°C to 120°C Accelerator pedal not actuated Engine speed in range of 570 RPM to 1000 RPM Braking torque is at least 250 Nm and brake light switch (S9/1) is actuated Transmission-internal uphill slope calculation value Transmission mode "C" or "S" selected 1st gear engaged by fully integrated transmission control and no off-road gear, or the Offroad-Program button (N72/1s25) is not active VGS operating without faults

Function sequence

The VGS reduces the flow at the brake control solenoid valve B2 (VGS) in such a way that the shift pressure is reduced to the backpressure spring level via the regulating valve B2 and BR and the multidisk brake B2 is converted to a regulated slip. This reduces the transmission output torque when the vehicle is stationary and reduces consumption.

The function sequence of "no power" in gear range "D" is deactivated when at least one of the following conditions is met

1. Vehicle speed v > 0 km/h
2. Transmission oil temperature t > 110°C
3. Coolant temperature t > 120°C
4. Accelerator pedal actuated
5. Engine speed n < 570 RPM or n > 1000 RPM
6. Braking torque < 250 Nm or brake light switch not actuated
7. Transmission-internal uphill slope calculation value > 25 %
8. A touch shift operation was detected or the DIRECT SELECT gear selector switch was switched out of gear selector switch position "D" to "N", "R", or "P"
9. A VGS system fault was detected

Gear change, function - GF27.60-P-3010GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 204.0, 216, 221, 251.0/1 up to Model Year 8

Each gear change is triggered by the fully integrated transmission control (VGS). In the process one component group is assigned to each shift operation.

One component group consists of the respective control solenoid valve, the regulating valve involved, the responsible shift valve and the necessary multi-disk brake or necessary multi-disk clutch.

The pressure in the multidisk brake or multidisk clutch to be engaged is increased constantly while at the same time the pressure in the multidisk brake or multidisk clutch to be disengaged is reduced. In the process a flowing transition is involved, but nevertheless the components affected are actuated directly and as a result enable downshifting via several gears.

Manual drive mode selection, function - GF27.60-P-3011RT

TRANSMISSION 722.9 in MODEL 251.0/1 up to Model Year 8

Scheme 256

With the DIRECT SELECT gear selector switch (S16/13) and transmission mode switch (N72/1s32) it is possible to adapt the automatic gearshift sequence to suit specific operating conditions. Although the shift range can be changed in the forward gears while driving, the electronic transmission control prevents a gearshift if the engine speed is too high.

Transmission modes except model 251.077/177

The driver can choose between transmission mode "C" and transmission mode "S".

In position "C" (comfort program) of the transmission mode switch compared to position "S" (sport program) a longer overall ratio and therefore a lower output torque is available when driving forwards and reversing. This allows the vehicle to move off more gently. In addition, the gears are not driven to maximum revs.

Transmission modes on model 251.077/177

The driver can choose between the transmission mode "C", transmission mode "S" and transmission mode "M".

In position "C" (comfort program) of the transmission mode switch compared to position "S" (sport program) a longer overall ratio and therefore a lower output torque is available when driving forwards and reversing. This allows the vehicle to move off more gently. In addition, the gears are not driven to maximum revs.

In position "M" (Manual program) of the transmission mode switch all forwards gears can be shifted directly by operating the following steering wheel shift buttons

1. Steering wheel gear shifter MINUS (S110/1), on model 251.177
2. Steering wheel gear shifter PLUS (S111/1), on model 251.177

A shift which would result in an unacceptably high or low rotational speed is not carried out.

Emergency default mode, function - GF27.60-P-3012AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of Model Year 09/Modification year 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of Model Year 09/Modification Year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of Model Year 09/Modification year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of Model Year 09/Modification year 08

Function requirements for limp-home mode, general

1. Circuit 87 ON
2. Circuit 61 (engine running)

Limp-home mode, general

In order to ensure safe driving and to prevent damage to the transmission, the fully integrated transmission control unit (VGS) (Y3/8n4) switches to limp-home mode in the event of critical faults. The fault is stored in the fault memory with the assigned fault code, and the CHECK ENGINE indicator lamp (A1e26) (with code (494) USA version) or the engine diagnosis indicator lamp (A1e58) (except code (494) USA version) is actuated in the instrument cluster (A1). In addition, the fault is sent to the ME-SFI control unit (N3/10) in the case of gasoline engines or to the CDI control unit (N3/9) in the case of diesel engines.

In the event of a hardware fault, all control solenoid valves are switched off and the transmission switches to 6th gear.

After gear range "P" is engaged, gear range "R and D" can be engaged.

In gear range "D", the transmission shifts to 2nd gear.

If hydraulic faults occur, the transmission remains in the gear currently engaged.

In the event of control solenoid valve faults, the affected gear is disabled and no longer actuated.

As a result the vehicle can be brought to the nearest Mercedes-Benz service operation.

Diagnosis

Up to 16 faults can be stored simultaneously in the fault memory. These can be read out using the Diagnosis Assistance System (DAS).

Emergency default mode, function - GF27.60-P-3012SX

TRANSMISSION 722.9 in MODEL 216,221, 251.0/1 up to Model Year 8

In order to ensure a safe driving state and to prevent damage to the automatic transmission, the electric controller unit (VGS) (Y3/8) switches to the limp-home mode if critical faults occur. In the event of a hardware fault all the control solenoid valves are switched off. They are then de-energized. In limp-home mode the transmission engages 6th gear. After gear selector switch position "P" is engaged, 2nd gear is engaged in gear selector switch position "D". Reverse gear "R" is available with the transmission ratio used for transmission mode "S". As a result the vehicle can be brought to the nearest Mercedes-Benz service operation.

If hydraulic faults occur, the transmission does not shift out of the gear currently engaged. If the fault is in the control solenoid valves, the gear affected is locked out and cannot be engaged anymore.

In the fault memory up to 16 errors can be stored simultaneously. They can only be read out using STAR DIAGNOSIS

Working pressure, function - GF27.60-P-3013GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 216, 221, 251.0/1 up to Model Year 8

The oil pressure produced by the oil pump is converted into working pressure by the working pressure regulating valve. The level of operating pressure depends on the position of the regulating valve and thus on its geometry.

The position of the working pressure regulating valve is influenced by the working pressure control solenoid valve (VGS) (Y3/8y1) in terms of load and gear. All other pressures required for the transmission control are derived from the working pressure.

Shift pressure, function - GF27.60-P-3015GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 204.0, 216, 221, 251.0/1 up to Model Year 8

The shift pressure (pressure in the multi-disk clutch or in multi-disk brake) is derived from the working pressure. The respective control solenoid valve influences the position of the associated regulating valve. In turn the position influences the pressure prevailing in the multi-disk brake or in multi-disk clutch.

The pressure thus depends on the geometry of the respective regulating valve.

Control valve pressure, function - GF27.60-P-3017AHZ

TRANSMISSION 722.902/903/904/906/907 in MODEL 164.1 as of Model Year 09/Modification year 08 Model refinement package

TRANSMISSION 722.902/903/904 in MODEL 164.8 as of Model Year 09/Modification Year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.0 as of Model Year 09/Modification year 08

TRANSMISSION 722.902/904/906/999 in MODEL 251.1 as of Model Year 09/Modification year 08

Control valve pressure function requirements (control valve supply pressure), general

1. Circuit 87 ON
2. Circuit 61 (engine running)

Control valve pressure (control valve supply pressure), general

The control valve supply pressure is drawn from the working pressure and is limited to a maximum pressure of 8 bar.

2 supply pressure regulating valves are used.

1. Supply pressure 1 regulating valve
2. Supply pressure 2 regulating valve

Supply pressure 1 regulating valve

Supply pressure regulating valve 1 supplies the following control solenoid valves

1. Working pressure control solenoid valve (VGS) (Y3/8y1)
2. K2 clutch control solenoid valve (VGS) (Y3/8y3)
3. B2 brake control solenoid valve (VGS) (Y3/8y6)
4. Torque converter lockup clutch control solenoid valve (VGS) (Y3/8y8)

Supply pressure 2 regulating valve

Supply pressure regulating valve 2 supplies the following control solenoid valves

1. K3 clutch control solenoid valve (VGS) (Y3/8y2)
2. K3 clutch control solenoid valve (VGS) (Y3/8y4)
3. B1 brake control solenoid valve (VGS) (Y3/8y5)
4. B3 brake control solenoid valve (VGS) (Y3/8y7)

By using two supply pressure regulating valves, the control solenoid valve groups are isolated from each other and the control solenoid valve groups do not influence each other during any shift operation

Control valve pressure, function - GF27.60-P-3017GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 216, 221, 251.0/1 up to Model Year 8

The control valve supply pressure is derived from the working pressure and is limited to a maximum pressure of 8 bar. 2 supply pressure regulating valves are used. Supply pressure regulating valve 1 supplies the following control solenoid valves

1. Working pressure control solenoid valve (VGS) (Y3/8y1)
2. Clutch control solenoid valve K2 (VGS)Y3/8y3
3. Brake control solenoid valve B2 (VGS) (Y3/8y6)
4. Torque converter lockup clutch control solenoid valve (VGS)Y3/8y8

Supply pressure regulating valve 2 supplies the following control solenoid valves

1. Clutch control solenoid valve K1 (VGS)Y3/8y2
2. Clutch control solenoid valve K3 (VGS)Y3/8y4
3. Brake control solenoid valve B1 (VGS) (Y3/8y5)
4. Brake control solenoid valve B3 (VGS) (Y3/8y7)

By using the supply pressure 1 regulating valve and supply pressure 2 regulating valve the control solenoid valve groups are isolated from each other and when there is no shift (via a gear) there is a reciprocal influencing of control solenoid valve groups.

Shift from 1 to 2, function - GF27.60-P-4013GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 216, 221, 251.0/1 up to Model Year 8

Multidisk brake B2, multidisk brake B3 and multidisk clutch K3 are engaged in 1st gear. When shifting from 1st gear to 2nd gear, multidisk brake B3 is switched off and multidisk brake B1 is switched on.

The shift operation is started by the fully integrated transmission control (VGS) control unit (Y3/8n4). In the process multidisk brake B1 is filled and the pressure in multidisk brake B1 increased. Simultaneously the pressure in multi-disk brake B3 is reduced.

This involves a flowing transition. When the 2nd gear torque is reached, the engine speed must be adapted to the 2nd gear level (elevation phase). This speed adjustment is achieved by the pressure in multidisk brake B1 being increased and if necessary engine torque being reduced via the ME-SFI [ME] control unit (N3/10) or the CDI control unit (N3/9).

Shifting N to D (1st gear), function - GF27.60-P-4014GZ

TRANSMISSION 722.9 in MODEL 164.1/8, 216, 221, 251.0/1 up to Model Year 8

In the "N" position of the gear selector switch for DIRECT SELECT (S16/13) the multi-disk brake B3 and multi-disk clutch K3 are engaged. By shifting from position "N" to position "D" the supply to multi-disk brake B2 is released by the selector valve. The fully integrated transmission control (VGS) control unit (Y3/8n4) actuates the brake control solenoid valve B2 (VGS) (Y3/8y6) and the multi-disk brake B2 is filled with transmission oil.

The RPM difference (actual slip) of the engine speed relative to the turbine speed is used by the fully integrated transmission control (VGS) control unit to determine whether the multi-disk brake B2 is filled. The brake control solenoid valve B2 (VGS) actuates the regulating valve B2/BR which converts the applied working pressure into shift pressure and passes it on to the multi-disk brake B2.

The slip required (specified slip) for each gear is stored in the fully integrated transmission control (VGS) control unit. Depending on this the brake control solenoid valve B2 (VGS) changes the control pressure on the regulating valve B2/BR. The shift pressure produced by the regulating valve B2/BR depends on the geometry of the regulating valve B2/BR. The pressure in multi-disk brake B2 is then continually altered until the specified slip stored in the fully integrated transmission control (VGS) control unit is reached.