To make a long story short I changed the left axle twice and it still leaked. I figured the groove must be too deep were the seal rides on the axle. I bought a low miles axle and a new seal and it still leaks. I'm thing it could be two different things. First I used an aftermarket "national" seal all three times, and second I have a TA girdle with the fill plug way at the top. Either way I'm going to use a GM seal on the next try.

Do you think that the higher fluid lever you get with the girdle would cause it to leak? I'm out of ideas and am down to letting it leak until it finally gets below the edge of the seal like it would be with an OEM diff cover.

Has anyone else ran into this problem?

Thanks guys

 

How did you install the seal. I like to put a little grease on the back of the seal to keep that spring from popping out during installation(if that happens the seal will leak). Then I will put a little oil or lubriplate around the seal so it slides in better and make sure the seal goes in straight .

If there is any grooves or knicks in the axle housing that can cause it to leak also(usually happens when taking the old seal out).

 

Yes the seal was lubricated well and there are not any grooves or knicks.

 

Anyone else have an idea?

 

Yep, you diagnosed your own problem, you have too much fluid in your axle. I also have an aftermarket "girdle" type cover and just because the fill plug is way up there on the cover doesn't mean you add fluid to that level! Here's the way to get a proper fill level on your differential. Open up the original GM fill plug located on the axle housing itself, (this is the fill location you would use if you didn't have the aftermarket cover). Now add fluid through your aftermarket top axle cover "fill hole" only until you see fluid coming out of the original fill plug location on the axle housing. Once you see fluid coming out of the original fill hole on the axle housing, put both plugs back in and you're done.

I've used the "National" brand axle seals many times on various F-Body setups and they are NOT your problem. Any axle seal will eventually leak when you have too much fluid in there. Fill your axle the way I've described above and you'll be good to go!

 

Thank you so much for the response. I was almost sure that was the problem but it helps to have another opinion as well.

thanks again