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20.6 Rear Axle

Check the pinion flange for excessive play. Usually slop here will result in a destroyed ring and pinion.

While inspecting the brakes, check for any signs of gear oil on the backing plates or brake shoes. Gear oil that has leaked past the seal at the outboard end of the axle tube will saturate the brake shoes and destroy them. The axle seal is not overly expensive or difficult to replace, but the axle shaft will sometimes have damage on its seal surface.

Although it is relatively rare for semi-floating rear axle bearings to fail, it is not impossible, particularly if the differential gear oil has not been changed regularly. Because the axle shaft rides directly on the roller bearings, it can sometimes be damaged.

Full floating rear axle bearings are often neglected, particularly in markets where both semi and full floating axles were offered. They should be re-packed/adjusted with the same frequency as front wheel bearings. If the rear wheel bearings are alowed to get out of adjustment, the hub will be allowed to deflect, which will cause it to try to misalign with the axle flange. Over time, this can cause the studs between the axle shaft and hub to loosen or even break. In addition to the six studs between the axle shaft and hub, full floating axles also have two dowel pins on each side. These hardened dowel pins are intended to bear a large amount of the torque transmitted through the axle shaft. If the vehicle has been driven with loose studs, the holes the dowel pins sit in can become oval shaped, which forces the studs to bear the all the torque which increases the likelihood of sheared studs. Fixing the problem requires drilling out the holes to accept larger dowel pins. Fortunately, the factory dowel pins used prior to 2002 are 7mm, so more commonly available 8mm pins are a simple upgrade.