Changing Rear Oil

crepitus · March 17, 2008

So I wanted to change the rear oil in my 06 Sierra. I went to the local parts store because they told me they had the rear diff gasket. When i get there they say it doesnt need one to use rvt. is this true or is there a gasket needed?

grimmysnr · March 17, 2008

If u have the eaton locker there will be a rubber gasket that is reusable there already. If not then i have heard you will need RTV. The gasket they mention is for one that needs to be replaced. Obviously, you wont know until you take the cover off. I would buy the gasket, take the cover off and inspect the one you have. If it looks worn or whatever replace it if not leave the old one. Im not exactly sure how it adheres to the cover though, GM adhesive maybe? I didnt replace mine so i didnt bother. Being an 06, honestly, you shouldnt have to replace yours yet either.

silveradocoa · March 17, 2008

we always put a gasket on any we do

crepitus · March 17, 2008

i do have the locker int he rear. so then do i need a gasket? i guess you have to get them from the dealer because i have called 5 different parts stores and no one lists the gasket. they say to use rtv

grimmysnr · March 17, 2008

RTV is like 10 bucks. I always have some anyway. Honestly, i think youll be fine without a gasket. Your truck is too new to be blowin out the gasket. Just pop the cover and drain everything, be sure to wipe out the old oil too.

My vote, is to not bother with a gasket, even if its bad youll know. Then just go buy one if its not leaking now it wont leak enough for you to drive to the parts store.

alaska511 · March 17, 2008

I have personally never used a gasket, and change mine annually on every truck I have ever had. Ultra Grey RTV is what I use. Yes with the G80

Genuinefine409 · March 17, 2008

i do have the locker int he rear. so then do i need a gasket? i guess you have to get them from the dealer because i have called 5 different parts stores and no one lists the gasket. they say to use rtv

I don't know anybody that uses a gasket for the rear diff cover. RTV is way better than the crappy gasket. you'll be fine with RTV, just make sure you get both surfaces clean and oil free so it'll seal good.

Don't they have drain plugs anymore? my 2000 S10 xtreme has the 8.5 rear and it has a drain plug in bottom of housing.

crepitus · March 17, 2008

should i lay a bead of it down or just coat both sides with it?

ken1mod · March 17, 2008

Just a tip. Make sure the fill plug is out before you drain. I have heard many instances where the oil is drained and the plug is stuck solid.

Ken

C & A s Dad · March 17, 2008

Ken is correct. I would also suggest you have a 3/8 drive piece that is square on the end. Many ratchets or pull handles and extensions have rounded corners. The drain plug hole is very shallow and these rounded corners do not fit very well causing you to round out the hole. They make special tools for this but you can find a 3/8" male piece that is squared off.