My rear diff has been leaking for years while my 82 CJ5 has sat and sat. I am in the middle of changing the gasket, and there is blue silicone in addition to the gasket... Is this needed? The sealant does not touch the gasket. There is nothing in my books.
84 CJ7 4 banger-owned since new in 1984 bought off truck at dealership - rebuilding 258, T176 with Sniper EFI D300 4:1 Lomax gears Twin Sticked 1 piece axels with locker
As far as I am concerned, the cork gasket is fine. Adding a slight amount of silicone sealant is OK as long as it just to act as a buffer. What the sealant was probably used for is that your cover is not completely flat, ( ego warped). Check your cover.
BTW, blue rvt is really only for situations that have extreme problems. See the attached data sheet.
Last time I did my rear diff I only used RTV, mainly because I didn't have a new gasket to put on because I was not expecting to have to pull my diff cover. That was 2 1/2 months and no leaks yet and mine is my DD. I used red RTV because that's what I had in the toolbox.
I do have a new gasket now that I will be putting on as soon as I get the opportunity.
I used the reusable lube locker gasket in my Dana 30 front axle years ago. I've had it apart a number of times. It's starting to look a little ragged but still seals good.