Automatically Controlled All-Wheel Drive (4Matic), Function - GF28.00-P-0001AVJ
Model 253 with transmission 725.096
Block diagram
Automatically-controlled all-wheel drive (4MATIC) in general
The automatically controlled all-wheel drive (4MATIC) is a permanent all-wheel drive with interaxle differential.
The separate transfer case is fitted to the transmission housing. Due to the design, there is the advantage that there is no reciprocal damage due to contamination (e.g. due to metal abrasion) through the separate oil circuits (of the automatic transmission and of the transfer case).
The lubrication is designed as splash lubrication. A transmission oil heat exchanger is fitted on the transfer case to cool the transmission oil. The transmission oil heat exchanger is connected to the low-temperature circuit of the engine cooling system, and it is supplied with coolant from the circulation pump 3 for the low-temperature circuit.
The pre-lock torque of the transfer case of 40 to 50 Nm is used to improve traction at low engine torque and to avoid any vibrations in the drive system. The drive torque distribution is adapted variably to the ground and driving situation. The drive torque is distributed over a single-speed transfer case without off-road ratio to the drive axles (drive system).
The all-wheel drive control unit controls the corresponding drive torque distribution through the integrated all-wheel drive control unit. The electric power steering control unit transmits the steering wheel angle to the all-wheel drive control unit via the suspension FlexRay. If, during comparison with the signals of the Electronic Stability Program control unit, understeer or oversteer is detected, the all-wheel drive control unit regulates the drive torque distribution via the integrated all-wheel drive actuator and the multi-disk clutch. The drive torque is distributed over a single-speed transfer case without off-road ratio to the drive axles.
View of multi-disk clutch actuation
Further subfunctions are described in the appropriate service information documents:
- 4MATIC transfer case, function
- Front axle transmission output 4MATIC function
- 4MATIC front axle transmission, function
- Oil supply for 4MATIC transfer case function
- Transfer case oil cooling system, function
- 4MATIC electronic traction system, function
| Automatically regulated all-wheel drive (4MATIC) torque distribution | GF28.00-P-0001-02AVJ | ||
| Automatically controlled all-wheel drive (4MATIC), technical data | GF28.00-P-0001-03AVJ | ||
| 4MATIC front axle transmission output, function | GF28.10-P-1012AVJ | ||
| 4MATIC transfer case, function | GF28.10-P-1000AVJ | ||
| 4MATIC front axle transmission, function | GF33.10-P-3000AVJ | ||
| Oil supply for 4MATIC transfer case function | GF28.55-P-3010AVJ | ||
| Transfer case oil cooling system, function | GF28.55-P-1002AVJ | ||
| 4MATIC electronic traction system, function | GF42.35-P-1000AVJ | ||
| Overview of system components, automatically controlled all-wheel drive (4MATIC) | GF28.00-P-9998AVJ |