Traction-Lok Differential Rebuild - Carbon Plating

Soak all the friction plates in Ford's XL-3 friction modifier for 15 minutes. No friction modifier was included in the M-4700-C kit, but it is available from your local Ford dealer.

Keep each set of friction plates, steel plates, and shims together, as they come premeasured and matched. Each set goes on one of the side gears. You might not be able to see it in this picture, but the side gears are splined to fit over the axles.

Install the clutch-pack and side-gear assemblies back into the differential. Ford recommends starting with the left side.

Next come the two spider gears. They spin back in as easily as they came out.

Finally, press the new spring into place, completing the Traction-Lok assembly. Some people use a rubber hammer to force the spring, while others compress it in a vise or with pliers first.

Bolt the ring gear back onto the differential using a vise. Torque the bolts to 70-85 lb-ft using a crisscross pattern.

Reinstall the rebuilt differential, complete with its carrier bearings and races. Put the caps and their bolts back where they came from, and torque the cap bolts to 70-85 lb-ft.

Though we had all shims and bearings reinstalled the way we found them, Dan still checked the backlash using this dial-indicator setup just in case. If your backlash isn't within 0.008 to 0.012 inch, add or subtract different amounts of side carrier shims.

With the differential installed, it's time to slide the axles back into place and reinstall the C-clips and center pin.

First clean off all the old gasket and gasket sealer from the differential housing. Dan recommends using only silicone gasket maker instead of the rubber gasket supplied with the new diff cover. The gaskets have a tendency to compress later, allowing leaks and causing the bolts to loosen.

We installed the FRPP diff cover (PN M-4033-G1) before the silicone dried and tightened the bolts to 20-25 lb-ft in a crisscross pattern. The thickness of this aluminum cover adds strength to the housing.

These special load bolts also support the main caps, which are under stress during launching and accelerating. Torque the load bolts to 5-10 lb-ft, then tighten the jam nuts to 25-30 lb-ft. Don't overtighten or you'll damage the differential bearings. Refill the differential with fluid and you're good to go.