4MATIC Transfer Case, Function - GF28.10-P-1000AVG

MODEL 205, 253 with transmission 725.041 

Transfer case, general 

The transfer case is bolted on to the housing of the automatic transmission.

The lubrication system for the transfer case is designed as a splash lubrication system without any external cooling.

The design of the transfer case has the following advantages:

• The transmission (automatic transmission and transfer case) can be separately repaired or replaced when defective.
• In case of repair, certain components of the transfer case can be replaced. A complete replacement of the transfer case is not necessarily required.
• The separate oil circuit means that there is no reciprocal impairment (automatic transmission and transfer case) through soiling (e.g. through metal abrasion).

Sectional view of transfer case, shown on double planetary gear set 

Courtesy of MERCEDES-BENZ USA

The planetary gear set acts as a planetary gear differential (3) between the front and rear axle. This then distributes the engine torque.

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 drive train.

The drive torque distribution on all vehicles except right-hand drive ones with engine 651 with 150 kW, 45 % on the front axle and 55 % on the rear axle is realized in the form of a double planetary gear set.

On right-hand drive vehicles with engine 651 with 150 kW, the drive torque distribution is 31 % on the front axle and 69 % on the rear axle, and is realized in the form of a single planetary gear set.

The transfer case is a single-speed design without off-road ratio. A universal joint is integrated into the front axle transmission output (6).

The single-speed version means that a spur gear set including mounting is no longer required. This acts positively on the efficiency, weight and noise characteristics for the drive train.