The seal is too keep the oil from getting out on to the brakes. The manual says to pack the wheel bearings, this is to keep them alive the first few miles after a service. I just pulled my rear brake off my truck, I personally put it together probably 15,000 miles ago with no grease, and oil came running out. I lightly lube the bearings with oil, and install. AFter getting the axle in and all repairs done, the rear diff is either filled or topped off, then I jack up one side of the axle so oil can run down hill into the wheel bearings, then jack up the other side so oil can get to the other bearings. No problems after that.
The rear wheel bearings are lubed by gear oil from the diff.
Michael
The rear wheel bearings are lubed by gear oil from the diff.
Michael