To remove and install a Differential Seal on a vehicle, first, loosen the rear wheel lug nuts, raise the rear of the vehicle, and support it securely on jack stands. Disconnect the 
Drive Shaft from the differential and use an inch-pound torque wrench to check the torque required to rotate the pinion. Scribe or punch alignment marks on the pinion shaft, nut, and flange, and count the number of threads visible between the end of the nut and the end of the pinion shaft. Use a special flange-holding tool or immobilize the flange to remove the pinion nut and withdraw the companion flange. Pry out the old seal and discard it. To install the new seal, lubricate the lips with high-temperature grease and tap it evenly into position. Align the mating marks and install the companion flange, applying non-hardening sealant to the ends of the splines visible in the center of the flange. Install the washer and pinion nut, tightening it carefully until the original number of threads is exposed. Measure the torque required to rotate the pinion and tighten the nut in small increments until it matches the figure recorded, staking the nut to the groove in the pinion shaft using a hammer and punch. Finally, connect the driveshaft, install the wheels, and lower the vehicle, tightening the lug nuts to the torque specifications.