Pinion Seal Replacement Cost Estimate

This difficult task is more physically taxing than anything, but also requires knowledge of setting preload on the pinion shaft bearing. Preload is the measurement of force applied to a bearing, and is measured by the force required to turn the pinion shaft. In some cases, the original position of the pinion gear nut can be marked against the pinion shaft flange, but this is not the proper procedure for all vehicles. In a worst case scenario, the differential cover is removed, and the differential is drained of oil. Then, the driveshaft and pinion shaft nut are removed so the pinion shaft seal can be pried from the differential housing. The new seal is installed with a drift, and the flange and nut can be reinstalled, but not tightened. Now, the drive axles, of various types, can be removed from the differential so the reload measured does not include the force of rotating the axles. Setting the preload for the bearings requires torquing the pinion nut, checking the force to turn the pinion shaft, and repeating until the pinion shaft turns at the specified tension, according to the service manual for the particular vehicle. Once complete, the driveshaft, axles, rear differential cover, and fluid may be replaced. Note, this is not a complete how-to, and there are vital steps which vary for individual vehicles, following the service manual is extremely important.

Replacing the pinion shaft seal can be a daunting task, and one that should not be repeated. To avoid mistakes in the process of replacing the pinion shaft seal, follow the instructions in your service manual exactly, and ensure only the proper tools are used for the job. In some instances, the seal can be replaced, and preload returned by placing witness marks (alignment marks) on the flange and nut, this prevents the need to measure preload and remove variou components, but is not applicable to all models.

If the service manual calls for replacement of the crush sleeve on the pinion shaft, the shaft must be removed from the differential, and new bearings, crush sleeve, and bearing races should be installed. This will greatly influence the cost of the repair, and a certified technician should perform the task. The amount of torque needed to successfully set the preload on a pinion shaft nut is typically more than a standard breaker bar or torque wrench can handle, and tightening this nut should be done with at least a one-half inch or three-quarter inch drive tool. Proper precautions and practice should be exercised to avoid injury during the torquing process.

When the seal may be replaced without replacing the crush sleeve, the job can be handled by an advanced DIYer with all of the appropriate tools. However, due to the risk of failure, injury, and damage to driveline components, this repair is likely best left to a professional.