Transfer Case (VG), Function - GF28.10-D-0002H

MODEL 906.131/133/135/153/155/231/233/235/253/255/631/633/635/637/653/655/657/731/733/735 with CODE (ZG2) Permanent all-wheel drive 

On vehicles with code (ZG2) Permanent all-wheel drive, a permanent all-wheel drive with one planetary gear set (in the transfer case) and 2 open differentials (in the rear axle and front axle) are used. The distribution of torque between the front and rear axle is predetermined by the planetary gear set in the transfer case and is 33 % to front axle and 67 % to the rear axle.

The special feature is dispensing with the mechanical inter-axle and inter-wheel locks. Instead, the all-wheel drive operates together with the electronic stability program (ESP) which is specially adapted to the all-wheel drive. The ESP switches on automatically if one or more wheels begin to spin on slippery ground. In these cases it selectively brakes the spinning wheel or spinning wheels or influences the engine torque.

As a result the drive torque increases simultaneously at the wheels which still have adequate road surface adhesion. Automatic intervention by the brake system by means of ESP can simulate the effect of up to 3 differential locks.

The permanent all-wheel drive increases the number of driven wheels, thus improving tire-to-road adhesion. As a result, slip is reduced and the driving power is distributed to all of the wheels. The distributed driving power means that a higher traction and higher lateral stability results at the wheels.