Axle Drive Pinion Seal
Leaks at the axle drive pinion oil seal originate for the following reasons:
- Seal was not properly installed.
- Poor quality seal journal surface.
Any damage to the seal bore (dings, dents, gouges, or other imperfections) will distort the seal casing and allow leakage past the outer edge of the axle drive pinion seal. The axle drive pinion seal can be torn, cut, or gouged if it is not installed carefully. The spring that holds the axle drive pinion seal against the companion flange may be knocked out and allow leakage past the lip.
The rubber lips can occasionally become hard (like plastic) with cracks at the oil lip contact point. The contact point on the companion flange may blacken, indicating excessive heat. Marks, nicks, gouges, or rough surface texture on the seal journal of the companion flange will also cause leaks.
Axle drive pinion seal wear 1.27 mm (0.050 inch) or greater is considered excessive.
The companion flange must be replaced if any of these conditions exist.
Metal chips or sand trapped at the sealing lip may also cause oil leaks. This can cause a wear groove on the companion flange and heavy pinion seal wear.
When a seal leak occurs, replace the seal and check the vent and the vent hose to make sure they are clean and free of debris.