question about rear diff fluid change

**parks31** · 02-14-2008, 04:40 PM

Hello, I changed the rear diff fluid on my 01 suburban 4x4 with 127k miles last week. I noticed today that it was leaking on my garage floor. I did everything like usual but I removed the gasket which was worn out and replaced it with a liquid/gel gasket. Anyone ever use this or should I find another rubber/foam gasket from the dealer.

**Pete95Sierra** · 02-14-2008, 06:23 PM

Get silicon gasket maker by Permatex and use that instead of a gasket. It is the blue one that I used on my diff and all of the trucks at my work but black will work too... it sells for like 5 bucks for a tube adn you can get it at auto zone. just squirt it around where the gasket would be on the diff and dont skimp on it

**parks31** · 02-14-2008, 07:40 PM

that is what I used. Maybe i did not let it sit long enough?

**Pete95Sierra** · 02-14-2008, 10:46 PM

wow ive never heard of any diff leaking when you put that stuff on there..... u prob just didnt put enough on or something... Id say try it again. and you shouldnt wait at all.... once you are done putting the silcone on put the cover back on right away and it will set and dry pretty quickly....

**cao88c** · 02-15-2008, 09:42 AM

When you put the RTV on it, you put it in a continuous bead about 1/4" thick any you go under the bolt holes. THe most important part is that you must let it sit for a while before you add the diff fluid. I usually let it sit 8 hours.

There is another gasket that they sell called "lubelocker", I have personally never used this on a rear end, but I know a lot of guys that swear by them. It goes on just like a regular gasket, and no need for RTV.

**MrShorty** · 02-15-2008, 11:34 AM

Make sure you know exactly what sealant you are using. I tried using a gasket maker by Permatex on a rear diff that didn't call itself RTV silicone that leaked gear oil like a sieve. Switched over to something known to be RTV silicone and the diff sealed right up.

Take the time to make sure you get the sealing surfaces (both the diff cover and the axle housing) clean of old gasket/sealant and oil. You have to be careful not to damage the sealing surfaces, but I usually use a razor blade to carefully scrape all the old stuff off. Then a little rubbing alcohol and a clean rag to get the oil residue off. Then apply the RTV and stick the diff cover on, usually just before bed. Let the RTV cure overnight and fill the diff the next morning.

**parks31** · 02-15-2008, 03:05 PM

thanks everyone. I am going to redo it and use a little more RTV and let it sit longer.

**collinsperformance** · 02-15-2008, 04:04 PM

i agree with the above. i normally clean real well razer blade and on the cover i wire wheel and repaint the cover if needed. i put a bead all around and let it "TAC" for 15 min then apply the cover and let sit over night then refill the diff and go and look the next day or at the end of a few long drives and verify it is still dry. ....mike