For 1990-2009 cars

The rear drive module (RDM) in this vehicle consists of a coupling control module and an aluminum housing which contains a clutch coupling assembly and a differential.

The on demand rear differential distributes variable torque/power to the rear wheels via individual axle shafts.

The on demand system operates as follows: only when front wheel slippage is encountered torque/power is proportioned to the rear wheels. As long as there is no front to rear speed difference; there is no torque/power to the rear wheels.

When front to rear wheel slippage does occur, the coupling control module receives the information from the ECM and BCM, then the coupling control module sends a signal to the clutch coupling assembly to actuate the clutch coupling pack which then distributes torque/power to the rear wheels. Rear axle output torque is controlled from 0 -2,530 N·m depending on various road condition such as asphalt, sand, snow and ice. The torque distribution ratio of front/rear axle is controlled continuously to have optimized value between 100/0-50/50 in real time depend on vehicle driving status and road condition.

The system has an integral protection device that reduces rear wheel torque when excessive heat is generated, thus protecting the rear wheel drive module (RDM).

### Rear Differential Assembly Fluid

The rear differential assembly uses a specifically developed synthetic hypoid fluid which is intended for a lifetime service interval. However, proper fluid level must be maintained to ensure proper rear differential assembly operation.