High-Performance Differentials, Axles, and Drivelines. Joseph Palazzolo

side of the aftermarket chrome cover for the GM 10-bolt, a curved bulge acts as a shelf that collects and diverts oil to the differential bearings. There is a similar feature on the right but it is not as pronounced.

      Also, while you’re at it, have the tubes welded to the cast center section. This not only stops those leaks, but also adds more support. Make certain to have a shop experienced with axles perform this work so that the housing does not get distorted from the heat of the welding process.

       A common chrome aftermarket GM 12-bolt cover features the distinctive oil shelf across the top portion of the cover. This makes these axles very easy to identify because it is the only axle with this style cover. The chrome plating adds a nice touch if you want a show part but does not really add any additional strength.

       Unlike stock units, aftermarket structural rear covers incorporate fill and drain plugs. Another great benefit is the differential bearing cap preload bolts. These are at the 3 and 9 o’clock positions of the cover.

      These housings are still highly sought after and can be pricey to acquire. Aftermarket units are available to help out with this shortage. There are even companies making 12-bolt housings to fit non-GM muscle cars.

Summary