Rear Drive Axle

Rear Drive Axle Description and Operation

Differential





The differential housing, side cover and pinion housing are constructed of cast aluminum. The internal components incorporate a hypoid gear set, ring and pinion, carrier assembly and pinion housing assembly. The pinion is supported in a pinion housing by tapered roller bearings. The pinion is positioned forward of the ring gear centerline. All models have a 7 5/8 inch ring gear. Each ring gear has specific setup dimensions, A1 and A2 values, stamped onto the side area of the gear. The A1 and A2 values are unique to each ring gear/pinion and are determined during the manufacturers gear/pinion noise and vibration setup and testing.

Pinion position, ring gear position and carrier bearing preload are determined by shimming procedures.

Rear Differential Temperature Sensor (RPO LSA)

The rear differential has a temperature sensor that monitors the fluid temperature. In the event the fluid temperature exceeds 160°C (320°F), the instrument panel cluster (IPC) will display a DIFFERENTIAL HOT REDUCE SPEED message until the fluid temperature drops below 150°C (302°F). If there is a malfunction in the rear differential temperature sensor circuit, the IPC will display a SERVICE DIFFERENTIAL SENSOR message and a DTC will be set in the IPC.

Differential Cooler

The differential cooler is designed to reduce the temperature of the rear differential fluid during high speed driving. The differential cooler system is controlled by a temperature switch (included with the differential cooler kit) located in the rear of the differential housing and functions when conditions require it to operate. The fluid capacity for the rear differential cooler is greater than the standard system.

The differential lubricant pump and cooler assembly is located under the vehicle and is mounted to the rear storage compartment well. The cooler module assembly consists of a pump, heat exchanger, electric fan, temperature switch, and assorted hoses/fittings. All components except the external lines, temperature switch, and fittings are located in the Cooler Module. Oil is pulled from the differential and pumped through a hose to the cooler/heat exchanger. The differential oil is cooled by dissipating heat as the 12 volt electric fan blows outside air over the heat exchanger. The cooled differential oil then returns to the differential. The differential cooler pump will not run until the differential fluid reaches 120°C (248°F). The pump and electric fan can be turned on by bypassing the temperature switch with the plug included with the wiring harness.