The eight-inch and nine-inch differentials were among the most popular differential produced by Ford in the 1960s and 1970s. Both designs were known for their durability, but the nine-inch featured a thicker casting and was commonly used in high-performance vehicles and trucks. As with all differentials, the nine-inch does require periodic servicing; fortunately, unlike many other differential designs, the nine-inch differential can be removed without having to remove its carrier, and disassembling the component is fairly straightforward.
Lift the vehicle with a floor jack and lower it onto safety stands positioned underneath the differential housings.
Remove the rear wheel and tire assemblies with a wrench.
Pull the brake drum off of the brake assembly to access the tip of the axle shaft.
Remove the three nuts that secure the tip of each axle shaft to the end of the differential housing. Note that the tip of the axle shaft features a hole; this hole is designed to serve as access point for the axle nuts. Turn the axle shaft until the hole aligns with each nut and remove the three nuts from each axle shaft with a socket wrench.
Pull the axle shafts out of the differential housing.
Remove the nuts that secure the driveshaft to the differential with a wrench, and lift the driveshaft off of the differential to expose the pinion nut.
Position a large container underneath the center of the differential.
Remove the bolts that secure the differential to the front of the differential housing with a wrench.
Pull the differential away from the differential housing just enough to allow the housing fluid to drain into the container, then lift the differential out of the differential housing.
Remove the two bearing caps that secure the differential case and the two circular adjusting nuts to the interior of the differential, and lift the differential case out of the differential. The differential case is the component to which the ring gear is bolted. Note that there are two caps, each secured with two bolts.
Remove the bolts located on the back of the ring gear with a wrench to separate the gear from the differential case.
Remove the pinion nut located in Step 6 with a wrench and slide the pinion gear out of the interior side of the differential.
Remove the bolts that secure the pinion retainer to the exterior side of the differential with a wrench and lift the retainer off of the differential.
