Differential Assembly: Description and Operation

Fig. 1 Limited Slip Differential System:

The 928 limited slip differential is an electronically controlled rear axle traverse differential lock, Fig. 1. A high pressure pump, pressure reservoir, solenoid and supply tank are incorporated into the hydraulic system, which is located on a holder in the left rear wheel housing. Power supply (fuse and pump motor relay) are located in the spare tire well.

The anti-lock brake system control unit incorporates an additional platinum board to provide lock control. The control unit uses information from the anti-lock brake system wheel sensors to determine wheel speed, wheel acceleration and deceleration, front to rear axle speed difference and right to left side wheel speed difference. A transverse acceleration sensor, located beneath the drivers seat, is also incorporated. Brake operation is monitored through the stop lamp switch.

When the control unit detects a slipping wheel, the system pressure will increase in steps until the slipping is operating with in the specified wheel speed range. The system will control traction during acceleration and acceleration and deceleration while cornering. A green lock information lamp on the instrument cluster will be illuminated when the locks are in operation and when both rear wheels slip.