Automatically Controlled All-Wheel Drive (4Matic), Function - GF28.00-P-0001AVO
Model 257.361, 290
up to model year 2021
Block diagram
Automatically-controlled all-wheel drive (4MATIC) in general
The automatically-controlled all-wheel drive (4MATIC) is a permanent all-wheel drive with variable torque distribution and an 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. It is equipped with an oil pump bolted to the outside of the transfer case. A transmission oil heat exchanger is fitted on the transfer case to cool the transmission oil.
The pre-lock torque of 40 to 50 Nm serves to improve traction at low engine torque while also helping to avoid any vibrations in the drivetrain. The torque distribution is adapted variably to the ground and the driving situation. 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 ESP® control unit, understeer or oversteer is detected, the all-wheel drive control unit regulates the torque distribution via the integrated all-wheel drive actuator and the multiplate clutch. The drive torque is distributed via a single-speed transfer case without off-road ratio to the drive axles (drive train).
The all-wheel drive control unit transmits the information "All-wheel drive operating mode" and "All-wheel drive error status" to the Drive Unit control unit and the ESP® control unit via the suspension FlexRay. The electronic ignition lock control unit also receives these signals and transmits them via the user interface CAN to the instrument cluster, which outputs a corresponding message.
Further subfunctions are described in separate documents:
- 4MATIC transfer case, function
- Front axle transmission output 4MATIC function
- 4MATIC front axle transmission, function
- Transfer case oil cooling, function (only model 290 with engine 177.9)
- Oil supply for 4MATIC transfer case function
- 4MATIC electronic traction system, function
| Automatically regulated all-wheel drive (4MATIC) torque distribution | GF28.00-P-0001-02AVO | ||
| 4MATIC transfer case, function | GF28.10-P-1000AVO | ||
| 4MATIC front axle transmission output, function | GF28.10-P-1012AVO | ||
| Transfer case oil cooling system, function | Model 290 with engine 177.9 up to model year 2021 | GF28.55-P-1002AVO | |
| Oil supply for 4MATIC transfer case function | GF28.55-P-3010AVO | ||
| 4MATIC front axle transmission, function | GF33.10-P-3000AVO | ||
| 4MATIC electronic traction system, function | GF42.35-P-1000AVO | ||
| Overview of system components, automatically controlled all-wheel drive (4MATIC) | GF28.00-P-9998AVO |