Rear Axle Assembly Description

The rear axle for this vehicle consist of the following components:

Rear Axle Assembly Operation

The rear axle receives torque from the propeller shaft and transfers it to the axle's pinion gear through the universal joint and the pinion yoke. The pinion gear transfers torque to the ring gear, which is splined to the drive pinion at a 90 degree angle. The ring gear is attached to the differential assembly. The only differential assembly available is the Torsen® limited slip differential.

Torsen® Limited Slip Differential Description

The Torsen® limited slip differential assembly consists of the following components:

Torsen® Limited Slip Differential Operation

The Torsen® limited slip differential combines the function of an open differential and a limited slip differential through the use of helical cut side gears and planet gears. The left side gear has helical teeth cut in the left-hand direction and the right side gear has helical teeth cut in the right-hand direction. The eight planet gears also have helical teeth, and are arranged within the differential case in pairs, which lie parallel to the axle shafts. In each pair, there is one left-hand helix gear and one right-hand helix gear. This arrangement allows the planet gears to:

This design allows only the four right-hand planet gears to mesh with the left side gear and the four left-hand planet gears to mesh with the right side gear. The planet gears in each pair also mesh with each other. With the gearing arranged as such, turning one rear wheel on the vehicle will result in the opposite rear wheel turning in the same amount, but in the opposite direction, as with an open differential. As a result, each wheel is able to compensate or differentiate for the different axle shaft and wheel speeds that occur when the wheel is turning without causing the tires to chip or hop.

The majority of limited slip devices function by generating internal friction - it is that friction which provides resistance to wheel spin. With a Torsen® differential, friction is generated when torque is applied to the helical shaped gear teeth. When torque is applied, an axial thrust force on the side gears will result and the side gears are literally pushed sideways apart from each other and against the inner walls of the differential case. At the same time, the loading on the gear teeth tries to separate the side gears and the planet gears. This pushes the planet gears outward against the walls of the differential case. Since the gears are being pushed against the differential case under load, friction is created. Because the friction that is created is a direct result of the torque applied to the differential by the drive train, the amount of friction that is generated is always in proportion to the amount of torque applied. This allows the Torsen® to differentiate freely when low or no torque is applied. Under power, the differential is essentially locked, allowing variations in traction under each tire to occur without spin or slip.

There is enough friction in the Torsen® differential to allow it to transfer approximately 65-70 percent of the total axle torque to the wheel with the greater amount of traction when the traction surfaces are unequal between the rear wheels. When this limit is reached, wheel spin may occur. However, the Torsen® will continue to send 65-70 percent of the available torque to the wheel with better traction, which allows the vehicle to move off of a slippery surface. In normal cornering there is enough of a difference in the load on each wheel to overcome the friction of the Torsen®, allowing the unit to differentiate while sending 65-70 percent of the total axle torque to the slower turning wheel.

The components of the Torsen® limited slip differential are not serviceable, the only repair is the replacement of the differential assembly.