Description And Operation: Overview

The twin speed transfer case is full time, permanent all wheel drive unit, with 50/50 torque distribution to the front and rear driveshafts. The transfer case is identical for all engine derivatives and supports the following features:

• Permanent all wheel drive with a bevel gear center differential, providing a 50:50 torque split
• Selectable high and low range for optimum on-road and off-road performance
• A pre-loading function, increasing locking torque with increased driving torque
• A slip controller to increase locking torque under off-road conditions and decrease locking torque for optimum comfort, for example during parking.

The twin speed transfer case is located under the vehicle and is mounted on the cross member, behind the automatic transmission.

The input torque is equally distributed via a bevel gear center differential. In order to provide an optimal torque distribution to each wheel in all driving conditions, the twin speed transfer case is equipped with an electronically controlled locking and torque-biasing device. This device detects wheel slip via various vehicle system inputs to the Transfer Case Control Module (TCCM) and locks the differential accordingly. The locking torque is applied through a multiplate clutch assembly.

A planetary gear set, located in the differential assembly, allows the driver to select high or low range. In low range, the planetary gear set provides a ratio of 2.93:1, which gives the vehicle an extremely low crawl speed for off-road driving and trailer towing. High range is a direct drive from the transmission output shaft and provides a 1:1 ratio.

The oil used in the transfer case is specially developed and contains unique additives, which enhance the transfer case operation. No other oil must be used in the transfer case.

A unique type of grease, fitting grease Weicon TL7391, must be applied to the transfer case input shaft spline when installing the transfer case.