06stangGT

Had FR 3.73's put in by a ford tech last weekend and i had the car up on a lift today and saw that the rear axle had fluid dried up on it around the diff breather. there was fresh fluid on the breather itself. No visible leak on or near the diff itself. Checked fluid level was ok. (had the master shim kit installed as well)

brought it to ford and they checked it out, they said its a normal condition ? ? ? The tech himself says that pressure builds up...duh, but its not suppose to come out the top like that right ??

I only have 3 days left on my warranty..they asked if i changed the gears. That shouldnt matter right ?

any input is appreciated

Lethaldosage423

if the diff gets over filled it should leak out a little. clean the area, drive for a while, let her sit for a while then check her again if its still leaking call FORD again

06stangGT

I ordered three qt's from brenspeed for the install, and the guy said he had a tiny bit left over that he didnt use in the bottle still. So i dont know if that means something else is wrong. The dealership called me back today and said they talked to the hotline and the hotline told them that it was because of the gears i put in causing too much pressure, or the type of fluid, (royal purple)

It is degreased but i dont want to drive it around with fear of the rear end blowing out...

pascal

Sounds like an overfill. How bad is it?
Drive it a couple of more weeks and see if it's oozing out still.

harraid5711

mine did the same thing after 4.10 install. the tech said it was due to overfill and was normal.

06stangGT

put it back on the lift today to find the fill plug leaking on the diff now.... was able to tighten the plug that was last touched by the dealership... wow.

moosestang

Mine does the same thing. 4.10's and royal purple. I know I over filled mine though. Do a google search for rear axle breather leak and you'll see a lot of completely stock vehicles do the same thing. Nissans fix was a longer breather tube, which i was going to install of mine just for the hell of it.

I wouldn't worry to much about it. Mine never leaks much, just enough to make the axle tube wet and dirt to stick to it.

Rubrignitz

Mine has been seeping since I had the 410's and trutrac installed over a year ago. I plan to swap the fluid this weekend with some amsoil 75w140 severe gear that arrived this week. We'll see how that works out... I don't think you have anything to worry about, the release is working as it should.

I actually PM'd moosestang about this many months ago after freaking out about it...

moosestang

Let us know how the amsoil works. I was thinking about trying that redline shockproof gear oil, but i'm not sure how well the LSD will work with that oil.

Rubrignitz

I definitely will. I pray at the Amsoil altar now . I used redline oil and shockproof gear (along with royal purple, who by the way I think makes some damn good gear oil, not so much motor oil) in my truck and 02 camaro exclusively but their claim of "flows like a 5w40" on their 5w30 oil made me leary of using it in the mustang (spec'd for 5w20).

The Amsoil goes in tomorrow, but FWIW they used amsoil 75w140 when they swapped my gears/carrier and I haven't had a problem. Just want to swap out again now after 15-20k to sweep any crap out.