Rear Axle Leak

[01YukonSC]

seems like it's been one thing after another with the Yukon lately...

I'm dealing with a rear axle leak that I'm not sure how to fix. I recently removed and resealed the differential and the leak doesn't seem to be coming from there. It is a replaced rear axle.

Pictures below showing where the leak is coming from on both sides. Seems to have gotten worse since I put new oil in.

How do I go about fixing this? If an extensive job, could I layer the outside around the axle with RTV as a hold over?

 

[01YukonSC]

Pics with markup

 

[Caveman]

I'm going to follow this cause my driver side is wet there also after I've done new axle seals. I thought it was just residue after I sprayed degreaser on the diff

 

[Dantheman1540]

Although its possible the axle tubes are spinning inside the housing I think its very unlikely. Its possible the differential breather line on top is leaking or maybe the brake line that runs on top of the axle.

 

[OR VietVet]

It is very very rare for an axle tube to leak. It happens but is rare. I think you are leaking at the cover and air is blowing it around or, like Dan said, the vent/breather is suspect. I would clean COMPLETELY off and get it COMPLETELY dry, check the fluid level and top off as needed and drive it and recheck. Check the breather/vent valve. They are supposed to be a one way valve.

This, axle vent valve, is the one for the front axle and the rear may look like this: https://www.rockauto.com/en/catalog/gmc,2001,yukon,5.3l+v8,1373105,drivetrain,axle+vent+valve,49456

 

[01YukonSC]

It's on both sides though and it is definitely differential fluid. Went to put more in to get a feel for how much has leaked out and it took about 1/4 of a bottle... Far more than I expected. Since I've refilled, it seems to be leaking faster also.

 

[01YukonSC]

It is an aftermarket rear end, original was shot about 7 years ago, just a few years after I bought it. Just as an FYI.

 

[OR VietVet]

You can guess or pinpoint the leak. Clean it and dry it and drive it and look at it. If you are correct and it is leaking fast, then a short 3-4 mile trip may be all that is needed. Longer trip may allow for the wind to blow the leak around and confuse the situation.

 

[01YukonSC]

If you look at the pictures, you can see the very bottom underneath the cover isn't wet and around the edges of the cover doesn't have oil either. It appears to come right out where I pointed and drain down to the left and right of the bottom of the differential.

 

[OR VietVet]

It is an aftermarket rear end, original was shot about 7 years ago, just a few years after I bought it. Just as an FYI.

Well, that makes all the difference in the world. Seen more axle tube leaks from them than OE. Still could have a bad vent not allowing the fluid to breathe.

The phrase "pulling teeth" comes to mind.


We recommend that you put all your rig(s) info in your signature so we all don’t have to guess at year, make, model, engine size, trans, rear axle locker…….etc. While you may have posted pertinent info in your first post, you may forget to do it again and the info is needed by us anyway. Makes it way easier on all members that attempt to help, to have that info right up front. It is also recommended that you take a pic of your RPO codes, on the inside cover of the glove box, and post that image in your signature. All this info will greatly help those that will try to help with a problem.


If there is any other info, like upgrades, mods or recent mechanical/maintenance work done, that would be helpful in any post as well. Too many times a question is asked by the poster and after about 10 responses we find out that the poster has done recent work to attempt to fix the problem or work that was done that SEEMS not related to the problem.