Torsen® Differential

TRANSFER BOX

DESCRIPTION AND OPERATION

41-15

Torsen® Differential

1 Bolt (3 off)
2 Cover plate
3 Pinion gear (6 off)
4 Thrust washer

5 Friction thrust washer
6 Side gear (front propshaft drive)
7 Side gear (rear propshaft drive)
8 Housing/ring gear

The Torsen® Type B traction differential unit is an integral part of the transfer box and is produced by Zexel Torsen 
of Belgium. The unit is a full time torque sensing and biasing system using parallel gearing for increased life and quiet 
operation.

During normal driving conditions, the Torsen® unit supplies a nominal 50:50 torque output to the front and rear drive 
shafts via the transfer box main shaft and the drive sprocket assembly.

The torque biasing capability consists of the ability to 'bias' the torque from the transmission to the axle and wheels 
with the higher grip. This must be achieved without causing wheel slip to the wheels of the axle with the lower grip 
within the biasing range of approximately 35/65 to 65/35 front to rear.

The torque biasing capability is instantaneous and operates as a preventative system. The unit does not need wheel 
slip and speed differentiation to be activated. The unit senses, via torque saturation within the unit, that one propeller 
shaft has the intention to rotate faster than the other one. The unit then biases the torque away from that propeller 
shaft and applies it to the other propeller shaft. Conventional systems require the wheel slip to occur first before 
initiating the torque biasing action. Because the Torsen® unit reacts before the slip occurs, the driving action is very 
smooth which results in enhanced grip for the road wheels.