Differential Cooler

Overview

The differential oil cooler increases axle performance and extends axle life by maintaining the differential oil temperature within a predetermined threshold. This is accomplished by the PCM through the use of a temperature sensor, an electric oil pump, a relay and an oil cooler.

System Operation

Differential Cooler

The PCM continually monitors the temperature of the rear differential lubricant. When the temperature reaches a predetermined threshold, the PCM activates the oil pump through the use of a relay. The oil is pumped to the cooler, cooled and returns to the differential. The PCM keeps the oil pump activated until the oil temperature is retuned to normal operating parameters. If the PCM is unable to reduce the oil temperature, a message is sent to the IPC to alert the driver through the message center. If the temperature continues to rise, the PCM sends another message once an upper limit threshold has been reached.

Component Description

PCM

The PCM monitors the inputs and any HS-CAN messages that relate to the differential cooler system and controls the oil pump activation.

When a new PCM is installed, the module must be programmed with the vehicle configuration information. For additional information on module programming, refer to Section 418-01 .

Oil Temperature Sensor

The oil temperature sensor is a negative temperature coefficient thermistor that is hardwired to the PCM. The electrical resistance of the thermistor decreases as temperature increases, and the resistance increases as the temperature decreases. The varying resistance affects the voltage drop across the sensor terminals and provides electrical signals to the PCM corresponding to temperature.

Oil Pump Relay

The oil pump relay is a 4-pin, mini ISO relay.

Oil Pump

The oil pump uses a single speed motor and an impeller to move the differential oil through the cooler system.

Oil Cooler

The oil cooler is a air-to-liquid heat exchanger utilizing cooling fins to dissipate the heat from the differential oil as it passes through the cooler.