Rear Axle Seal

Volucris · August 7, 2019

The seal on my rear right axle has failed multiple times. Twice under warranty way back when, and just recently. They truck has 140K miles on it. The second time it failed under warranty, they replaced the right axle and seal.

Anyone have an idea on why a seal would fail that often. Is there an irregularity i a casting, or machining I should look for?

dtnel78 · August 8, 2019

Could be when the tech working on it at the dealer or from the factory there may be a burr of some type where the seal sits.

One thing to do is just jack that side, the tire only a few inches off the ground and grab it and see if it wobbles up and down, side to side or in & out which may suggest bearing wear.

Also where the seal mounts to the tube housing there could be a slight nick in the area where the seal drives in. If so some black RTV around the edge of the seal mounting surface would be some help as my local transmission shop had to do on mine.

Another possibility could be the seal surface where the axle meets the seal is not smooth enough.

IF you can remove the caliper, brakes and rotor you can view from the backside carefully with a bright light and see which side it's coming from.

IF it's leaking from the backside then the RTV could help otherwise if from the axle assembly itself where it contacts the seal then you have to check the axle mating surface to see if a sleeve can be mated up to provide a smooth surface or replace the axle shaft from the center of the differential outwards.

This means you'd have to drop the fluid and remove the pin holding the diff assembly together and disassemble it and inspect for defects in the axle assembly.

I had something similar as I'd had my rear axle slide to the right and bump a curb and had to replace the seal 3 times. The 3rd time I'd taken it to the transmission shop and they cleared it up with the RTV on the axle. No issue in years "knock on wood"

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Volucris · August 8, 2019

Thanks for the input

the axle bearing is OK

There is a groove in the axle - but very slight. Probably polish it out. Groove is a bit of an exaggeration, it is a very small indentation. A few thousandths at most.

RTV is a good idea. Thanks.

New brake shoes - the ones I have are saturated with Differential Oil. It's a rear drum.

Seems odd that the right side seal fails three times, left side still good. Hell, that doesn't seem odd - it is odd.