Component Tests and General Diagnostics

Four-Wheel Drive Systems - Electronic Shift





Special Tool(s)

Principles of Operation Electric Shift
The front-wheel drive transaxle utilizes a transfer case unit to transfer power through a driveshaft and universal joints to the rotary blade coupling (RBC) mounted to the rear differential.
The mode select switch (MSS) has two positions: AUTO and 4X4 ON. In the AUTO position, the system is in two-wheel drive until the front wheels begin to slip. The spinning of the front wheels causes a relative speed difference between the front and rear axles and turns a rotary blade mounted in silicone fluid. The turning rotary blades builds pressure in the silicone fluid, which pushes a piston, compressing the clutch plates of the RBC and transferring torque to the rear wheels. The torque applied to the rear axle is a function of the difference in wheel speed between the front and rear wheels. When slip is no longer present at the front wheels, the system reverts to front-wheel drive.
The 4X4 ON mode energizes the four-wheel drive relay, which supplies power to the integral electrical clutch to lock the RBC and transfer power from the rotating driveshaft to the rear wheels. In the 4X4 ON mode all wheels are driven full-time until the switch is turned to another position.