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.