Limited-slip differentials are used in high-performance cars help transfer useful torque from one wheel with limited traction to the wheel with the most traction available, thereby improving handling and overall performance. The clutch packs used in these differentials become thinner as the friction material wears down with constant use. Replacing the clutch packs is a rather messy, yet necessary, job if you want to maintain the performance of your vehicle.
Loosen the rear wheel lugs with a lug wrench. Raise the rear end of the vehicle with a floor jack and support the vehicle with jack stands. Place wheel chocks behind the front wheels to prevent movement.
Place a drain pan underneath the differential. Loosen the bolts on the differential cover except the top two bolts with a socket wrench. Pry the cover loose with a slotted screwdriver and allow the gear oil to drain out into the pan.
Loosen the top two bolts and remove the differential cover. Clean away residue from the bottom of the differential with a shop rag.
Place the new clutch discs in a bath of friction modifier. Allow the discs to soak in the bath for at least 20 minutes.
Remove the lock bolt from the pinion shaft and carefully push the shaft out. Remove the wheel lugs and dismount the wheels from the vehicle, then remove the rear brake hardware from the axle.
Push the axles inward to reveal the C-shaped clips holding them in place. Remove the clips and pull the axles out carefully. Remove the S-shaped spring from the differential with channel locks.
Rotate the pinion gears and spider gears until both sets of gears pop out of the differential. Inspect these gears for wear and tear and replace them if necessary. Grab onto the metal tabs on the clutch pack discs with a pair of pliers and slide them out of the differential.
Remove the clutch discs from the friction modifier bath and arrange them in the following order, where “F” stands for “friction discs” and “S” stands for “steel discs:” F-S-S-F-S-S-F. Insert the clutch pack into the differential.
Insert the driver’s side axle into the differential. Summon a partner to turn the axle while you insert and lock the pinion gears and spider gears into place. Use channel locks to squeeze down the S-shaped spring while popping it back into place.
Reinsert the passenger side axle, then push both axles all the way into the differential. Insert the C-shaped clips into place and pull the axles back against the clips. Reinstall the pinion shaft, then lock the shaft into place with a new lock bolt.
Apply high-temperature gasket maker onto the inside of the differential cover where the surface mates with the differential itself. Attach the cover onto the differential and tighten the bolts with the socket wrench.
Place the drain pan underneath the differential fill plug, then remove the fill plug with the socket wrench. Place the spout on the gear oil container into the fill hole and pour the fluid inside until it starts draining back out of the hole.
Wipe the fill plug off with a shop rag and insert the plug back into the fill hole. Tighten the plug with the socket wrench.
Reattach the brake hardware and remount the wheels onto the vehicle. Finger-tighten the wheel lugs onto the rear wheels. Remove the jack stands and lower the vehicle to the ground. Tighten the wheel lugs onto the wheels with the lug wrench and remove the wheel chocks.
Drive the vehicle a short distance to allow the gear oil to circulate through the differential. Park the vehicle and inspect the differential for leaks.
