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Ford Differentials: How to Arrange Clutch Pack

by Joe Palazzolo

(Taken from Ford Differentials: How to Rebuild the 8.8 and 9 Inch by Joe Palazzolo) 


Over the years, clutch plates and steel reaction plates have come in many different orders. The most recent and effective is shown here (left) (from the gear to the shim): side gear, steel reaction plate, friction plate, steel reaction plate, steel reaction plate, friction plate, steel reaction plate, friction plate, and shim. So this clutch pack includes four steel plates, three friction plates, and one .020-inch-thick shim.

Notice that the steel reaction plates are splined on the inside diameter to align with the side gear; the friction plates are tabbed to align with the pockets in the differential case. Ideally you want the entire clutch pack, including the shim, to be about .640 to .645 inch for a stock clutch pack and as thick as .655 inch for a performance pack (right). In my opinion the thicker pack performs better and a few pops during turns from the clutch pack are acceptable because you know what is causing the pops and are not worried. Be sure you understand the pops if you are going to use the thicker pack values.

Here are all of the internal parts and gears of the limited-slip differential assembled just for visual reference. Keep in mind, you cannot install them in the differential case like this, but when the assembly has been rebuilt, all of these parts are arranged as shown. I leave the side gears and clutch packs pre-assembled as shown because they are ready to be installed in the differential case. Also the spherical pinion washers resting on the differential pin
are important to include during the re-assembly process because they act as the wear surface between the hardened pinions and the differential case. They are curved to match the differential case and back surface of the pinions.


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