Principles Of Operation

Power Transfer Unit (PTU)

Principles of Operation

The Power Transfer Unit (PTU) is a gearbox that attaches to the transaxle. The RH intermediate shaft passes through the PTU and engages the differential side gear as in normal Front Wheel Drive (FWD) applications. The PTU directs power to the rear driveshaft through a helical gear spline coupled to the transaxle differential case, a helical gear drop (idler gear) and hypoid/helical ring gear assembly and pinion set. The PTU is sealed from the transaxle and has its own oil sump.

Serviceable components of the PTU are limited to the output shaft seal and flange, intermediate shaft seal and deflector, the cover seal and the PTU-transaxle compression seal. The internal components are not serviced. Do not remove the cover of the PTU. If any of the geared components, bearings, case cover or internal shafts are worn or damaged, a new PTU must be installed.

Heat Protection Mode

During very extreme off-road operation, the All-Wheel Drive (AWD) system utilizes a heat protection mode to protect the Active Torque Coupling (ATC) solenoid (part of rear axle) from damage. If the system detects an overheat condition, it enters a locked mode. If the heat in the system continues to rise once in the locked mode, the 4X4 control module disables the ATC solenoid. Allow the system to cool down at least 10 minutes with the ignition switch in the ON position.

For concerns with the 4X4 control module or ATC, refer to Transfer Case.