GMC 12471523 Pinion Seal

To remove the rear wheel, start by loosening the lug nuts and raising the rear of the vehicle on jackstands. Disconnect the driveshaft and secure it out of the way. Use an inch-pound torque wrench to check the torque required to rotate the pinion on semi-floating axles and record the reading. Make alignment marks on the pinion shaft, nut, and flange, and count the number of threads visible between the nut and shaft. Use a special tool or large pliers to loosen the self-locking pinion nut. Remove the nut and withdraw the companion flange, using a puller if necessary. Pry out the old seal and discard it. Lubricate the new seal and tap it into position with a seal installation tool or large socket. To install, align the mating marks and install the companion flange, tightening the pinion nut if needed. Apply non-hardening sealant to the spline ends on the flange. Install the washer and pinion nut, tightening it until the original number of threads are exposed. Measure the torque required to rotate the pinion and tighten the nut incrementally until it matches the recorded figure, slightly exceeding it to compensate for the new oil seal. Connect the driveshaft, install the wheels, and lower the vehicle, tightening the lug nuts to the proper torque.