Leaking Rear Diff Cover Again

I did a search for this and nothing came up other than buying a new Ford Racing cover. I don't believe that should be necessary. When I sealed it last time I had the diff out on my bench cleaned it with brake cleaner on till it was spotless and sealed it with Motorcraft heavy duty silicone and let it cure overnight. It was good for 2 years and now it's seeping out between the cover, not the vent or output seals. If anyone has a fix I would like to try it. Thanks in advance for your help.

i think it’s all caused from brace on cover causing cover to lose seal. i need to redo my cover also and going to do it without removing rear from car. i had just done new gears 2ys ago.

Did you use gear oil gasket maker? Some silicone is not meant for diffs or transfer cases from what I understand

The ford grey is pretty stout. Let it set up just a hair before buttoning up.

If it’s just an occasional drip, you can try a product called seal all. Clean off what you can and then apply.

Normally this is kinda hacky doodle, but when I was a tech a corvette guy avoided like 1200 bucks in labor or something stupid by having us try it. It worked!


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Lube locker

Are you sure your OEM cover isnt ever so slightly warped? Or maybe it flexes when you throw power at it, breaking the seal?

Oh and the big question too - is it solidly mounted to the frame? Or are you still the using the stock front/rear diff bushings?

UncleSAm said:

Lube locker

Click to expand...

Used one of these as well when I changed out my cover. No leaks. No drips.

Lube locker and use studs instead of the cover bolts. That's the only thing that work for me and I beat on mine and high road coarse temps


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Motorcraft TA31 on the FRPP cover, 1-1/2" years - no leaks yet

Thanks for all the help, SVTP guys always come through.

I like the idea of the lub locker gasket and studs. For a temporary repair I will try the seal all, I think it's worth a try and if it doesn't work I'm not out much.

It is such a pain in the ass to pull, that I would do the Ford Racing Cover and be done with it.

Just an update I installed a Fore Racing rear diff cover. It's a beautiful and well made part and I'm sure it will solve all future leak issues.

I have just a few tips as I finished the install and now have had a track day since the cover was installed. First tip is take your time and mark the upper camber adjustment eccentrics so they can be set back to the proper position to avoid having to pay for a wheel alignment. The second tip is watch the fill level, the instructions indicate to fill the diff. until fluid is level to the fill hole. That caused a overfill in my car and caused fluid to be pushed out of the vent which made a big mess. The correct fill level according to the Ford service manual is 1/4- 5/16 inch below the fill plug. If I had done that it would not have pushed the fluid out the vent, this is not a huge deal but a big mess to clean up.

++ For the Lube Locker also. Seals very well and it is reusable. No more messy RTV to deal with.

Keep up posted after a few miles

I didn’t get to mine and toasted a pinion bearing.

I redid it but still oem cover and rtv

By any chance do you have part # for the lubelocker gasket??

It should be LLR-F880