Dodge Durango

 Service Manual

Transmission and Transfer Case » Description and operation
Overdrive clutch

DESCRIPTION

The overdrive clutch (Fig. 56) is composed of the pressure plate, two clutch plates, three holding discs, overdrive piston retainer, piston, piston spacer, and snap rings. The overdrive clutch is the forwardmost component in the transmission overdrive unit and is considered a holding component. The overdrive piston retainer, piston, and piston spacer are located on the rear of the main transmission case.

NOTE: The number of discs and plates may vary with each engine and vehicle combination.

OPERATION

To apply the clutch, pressure is applied between the piston retainer and piston. The fluid pressure is provided by the oil pump, transferred through the control valves and passageways, and enters the clutch through passages at the lower rear portion of the valve body area. With pressure applied between the piston retainer and piston, the piston moves away from the piston retainer and compresses the clutch pack. This action applies the clutch pack, allowing torque to flow through the intermediate shaft into the overdrive planetary gear set. The overdrive clutch discs are attached to the overdrive clutch hub while the overdrive clutch plates, reaction plate, and pressure plate are lugged to the overdrive housing.

This allows the intermediate shaft to transfer the engine torque to the planetary gear and overrunning clutch. This drives the planetary gear inside the annulus, which is attached to the overdrive clutch drum and output shaft, creating the desired gear ratio. The waved snap ring is used to cushion the application of the clutch pack.

42/44 Re transmission

Fluid

Torque converter

Oil pump

Valve body

Accumulator

Pistons

Front clutch

Rear clutch

Overdrive clutch

Overrunning clutch

Planetary gearset

Bands

Servos

Gearshift mechanism

Converter drainback valve

Powertrain control module (pcm)

Electronic governor

Governor pressure curves

Overdrive off switch