Flange Yoke Seal

WARNING: This page is about a different car, the 2013 Ford F-550 Super Duty, 2013 Ford F-450 Super Duty, 2013 Ford F-350 Super Duty, and 2013 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.

Leaks at the axle drive pinion seal originate for the following reasons:

Seal was installed incorrectly.
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 rubber lips can occasionally become hard and crack at the oil lip contact point. The contact point on the pinion flange may blacken. Marks, nicks, gouges or rough surface texture on the seal journal of the pinion flange will also cause leaks.

Install a new pinion flange if any of these conditions exist.

When a seal leak occurs, install a new seal and check the vent and the vent hose to verify that they are clean and free of foreign material.