Raise the rear of the vehicle and place it securely on jackstands, then remove the rear wheels, brake calipers, and Brake Rotors. Mark the driveshaft and companion flange for ease of realignment during reassembly, then remove the driveshaft. Mark the relationship between the pinion and companion flange. Using an inch-pound torque wrench, measure and record the torque required to turn the pinion nut through several revolutions, which will be used when the pinion flange is reinstalled. Hold the companion flange with a suitable tool and remove the pinion nut, then use a small puller if necessary to separate the pinion flange from the pinion shaft. Pry out the old seal with a seal removal tool, clean the oil seal mounting surface, and tap the new seal into place, ensuring it is inserted squarely. Inspect the splines on the pinion shaft for burrs and nicks, removing any rough areas with a crocus cloth and wiping the splines clean. Install the companion flange, aligning it with the marks made during removal, and gently tap it on with a soft-faced hammer until the pinion nut can be started on the pinion shaft. Hold the companion flange while tightening the pinion nut, stopping frequently to take rotational torque measurements until the previously recorded measurement is reached. If the recorded measurement was less than the pinion bearing preload torque, continue tightening until the specified torque is reached; if it was more, continue until the recorded measurement is reached, avoiding backing off the nut to reduce preload. Reinstall the driveshaft, Brake Rotors, brake calipers, and wheels, check the differential oil level and fill as necessary, then lower the vehicle and take a test drive to check for leaks.
