Rear end install (3rd member)


Mar 30, 2005
Danb., CT
I am ready to install my new third member 8" rear back into the car. I have a new gasket and have purchased RTV sealant. My question is do I need to use sealant? Should I use only sealant or if I use both, where do I put the sealant in relation to the gasket, housing and third member?

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Sealant is optional in this case.

If you think you might need to take it back apart in the next couple of years, I'd skip the sealant as it's a pain to clean off.

Otherwise, it can't hurt. Apply a thin film to both sides of the gasket and make sure the mating surfaces are clean and free of any oil residue.
I think it depends on if the rear-end is out of the car or you are laying underneath trying to install it. I'd use the sealant only if it was out of the car. If the rear-end is still mounted you'll have to wrestle with it a little to get it back in and your RTV will start to setup beafore you get itstalled and tightened down (unless its non hardening RTV.

P.S. I just saturate my gasket with bearing grease. This impregnates the gasket and seals real well. This is also good if you have to pull it back apart next week because something went wrong with the rebuild or your diff makes weird noises.
The rear is in the car and on stands, so I have about 16" of room. I do not plan on taking it out so hopefully all is good.

But you don't give an opinion either way. You actually made the decision a little harder.
I think if you read my post again you will see that I did give you my opinion.
I said I would use sealant only if the rear-end where out of the car. Since You now have stated that it is in the car then my suggestion is NOT to use RTV. You will have some trouble getting you third member back in because its heavy and awkward and sometimes they just wont slide back onto the studs easily.

So at this point I would suggest to not use RTV but instead use grease on both sides of the gasket.

Good Luck