The pinion seal of my vehicle keeps leaking and has been replaced twice?
Assuming the seal was properly installed, there are things that can result in repeated failure. A plugged axle vent can allow pressure to build and ruin a good seal. A bad pinion bearing can allow slack that the seal cannot control. A groove in the seal surface of the pinion flange can also result in repeated leaks. Finally a rear U-joint that is tight can cause a vibration that will quickly destroy the pinion seal.
