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Rear diff pinion seal leak?!?! Please help diag.

3356 Views 8 Replies 6 Participants Last post by  wjbertrand
Alright, a couple of months ago my pinion seal failed. There was oil that sprayed all around the diff, even onto the exhaust pipes in the area, and the underbelly of my car. That was about 6 months ago, and probably 10,000 miles. Today, i had my car in the air replacing the rims, and i noticed that the rear diff was wet again. This time its not near as severe as the first time, in fact its really not that bad, but there is still liquid on the differential. Unfortunately now, im about 700 miles out of warranty, and ford will no longer cover the repair. Everywhere i've read online the ford pinions are crap anyway. Is it normal to have just a little liquid on it? Should i go ahead and replace the seals, or just take some differential oil and make sure its always at the right level? HELP PLEASE :crying:
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First off,being that you are only 700 miles out of warranty, contact DEYSHA our Ford Customer Service Rep she might be able to get Ford to do a good customer good will repair under warranty.and NO to adding oil all the time get it fixed,you don"t want that mess under your car.
I would guess you have a clogged breather vent on your axle. It's there to release pressure as stuff gets hot. If it clogs, the pressure will need somewhere to go, and pinion seal and wheel bearing seals are the next easiest places for pressure to release.

Are you sure it's the pinion seal and not just spray from the breather vent?

Ford pinions are most decidedly NOT crap by the way- the Ford gearsets are great. It's the installation and setup of said Ford gearsets that can go awry.
Welcome to the site!
First off,being that you are only 700 miles out of warranty, contact DEYSHA our Ford Customer Service Rep she might be able to get Ford to do a good customer good will repair under warranty.and NO to adding oil all the time get it fixed,you don"t want that mess under your car.
Okay, What number do i need to call to get in contact with her?
PM her at FordService. She was out of the office for the holiday so it might take a day or two for her to catch up and get back to you. But she will.
I would guess you have a clogged breather vent on your axle. It's there to release pressure as stuff gets hot. If it clogs, the pressure will need somewhere to go, and pinion seal and wheel bearing seals are the next easiest places for pressure to release.

Are you sure it's the pinion seal and not just spray from the breather vent?

Ford pinions are most decidedly NOT crap by the way- the Ford gearsets are great. It's the installation and setup of said Ford gearsets that can go awry.
I think i jumped the gun on assuming it was the pinion seal. I think youre right. I got it back into the air yesterday and there was no over spray from what a busted pinion seal would have caused. When i actually ran my finger over the differential the fluid was dry. It wasnt soaking wet. I believe you are correct about it being just spray from the breather vent. Im sure the ford dealership just over filled my fluid, and the first time i pushed it, it probably just heated up and over flowed. Thanks for all your help. Now how do i delete this thread?
Even when properly filled these rear ends can blow lube out the breather. For as a TSB out for an improved breather, but from what I've read it's a temporary solution at best. There are a number of surge reservoirs available for not too much money. I bought a JLT one a and the axle / differential have remained clean and dry since.

JLT Rear Axle Expansion Tank (2005-14 Mustang) [JLT-AX05] - $119.00 : JLT PERFORMANCE, Home of the JLT TRUE COLD AIR KIT
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