Rear Diff Seal leak?

I know this may seem as a very lame question but most of my mechanical knowledge I picked up from reading this forum.

When people replace rear diff seals, this is supposedly what they fix right?



How often should I replace my diff oil?

pinion seal (front at the yoke)
cover gasket (rear at the cover)
axle seals (outboard behind the brake rotors)
ABS sensor o-rings (where they plug into the axle tubes).

That's pretty much all the places the rear can leak from.

So from my picture I should be replacing a cover gasket I assume?

Not necessarily, a little bit of oil goes a long way. When was the last time it was serviced? If they overtopped it a little out of the plug could spread to that pattern.

The gasket is a reusable gasket and should not need replacing even if the cover was removed. Doubt that you have a leak. Just open that fill hole with a 3/8" drive ratchet and make sure the oil is to the bottom of the fill hole

To be honest when I asked the dealer if they change the oil in the diffs they said no, claimed that the oil should last a very long time. Im now at 70K miles, should the oil be due for a change?

I have a similar leak from the drain plug.

Pretty sure yours is oil coming from the fill plug. You could undo to check the level, clean & re-install to the torque spec. Then get some spray brake cleaner (or degreaser) to clean off the residue. Drive it for a while then come back check.

If the leak is in the same place you may need to pull the plug & replace the washer.

This is what I now need to do but because mine is the drain I will need to get some diff oil as well.

Does any one know what washers are on the drain & fill plugs (I asked GM the said they don't sell the washers separate you have to buy the whole plug)

Yeah...I would consider that "ooze" and not necessarily a "leak". You can take your old drain plug to NAPA and get a new washer for it...nylon, rubber, copper, whatever.

Definitely a fill plug ooze from my angle. Bet your right it was fill a little too high and slowly finding its way out. I'd take a ratchet and give it a crank, maybe just a little loose.


"If at first you dont succeed, come back with a big damn stick". -My Dad
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