Rear Drive Axle Description and Operation (Without G99)

Fig 1: Identifying Rear Drive Axle System Block Diagram

Courtesy of GENERAL MOTORS COMPANY

The rear differential clutch control modules function is to control the electronic open differential. The rear differential control module calculates torque command internally according to the driving situation to achieve vehicle dynamics and traction.

The electronic differential system contains the following main components:

• The rear differential clutch control module
• The rear differential clutch motor
• The rear differential multi-disc wet clutches

When the torque signal is received, the rear differential control module actuates the following components:

• The rear differential clutch motor

The hydraulic piston engages the clutch to allow torque to the open differential.

The rear differential clutch control module monitors voltage levels, clutch temperatures, over-current, and circuit failures.

Whenever the hydraulic control system within the electronic differential system is opened, a service bleed procedure with a scan tool needs to be performed to remove any air from the system.

If replacing the rear drive clutch control module, the module needs to be programmed/configured with a rear differential clutch correction factors. The clutch correction factor value is an alphanumeric value that is stored in the rear differential clutch control module and stamped on the rear differential clutch pack housing. The clutch correction factors is based on the valve current-to-torque performance of the individual clutch pack. The clutch correction factor helps to improve vehicle performance by adjusting software parameters to suit the mechanical hardware.

Configuring the rear differential clutch control module with the clutch classification value might be required after certain service procedures are performed. An eight digit values will be used during the programming of the rear differential clutch control module using the scan tool.