Non-H2 stupid technical question
 

I'm going to change the diff fluids on my '99 Burb tomorrow. The rear diff requires a gasket (which I have).

My question is - Do I need any type of sealant when I use a gasket? Just rub a little fluid on the gasket to moisten it up?

Re: Non-H2 stupid technical question
 

Re: Non-H2 stupid technical question
 

Just WHAT on the cover side? What non-perm sealant/goop should I use?

Re: Non-H2 stupid technical question
 

When I work with gaskets I like to use Permatex Anerobic gasket maker. You dont need to cover the whole gasket, I run a streak between each hole, then let it "set up" for 20 or 30 minutes before you install it.

On another note. I dont know what type of diffs are in your Burb, but MAKE SURE that you do not need a friction modifer! If you do make sure to add it, you'll can really shorten the life of the diffs without it.

Re: Non-H2 stupid technical question
 

Put the gasket on the diff cover, not the diff itself.

Re: Non-H2 stupid technical question
 

:iagree: ;)

Re: Non-H2 stupid technical question
 

Thanks for the info.

Oh, and I had already checked - no friction modifier should be put in for GM 10-bolt/8.5 diff.

Re: Non-H2 stupid technical question
 

I use a very light coat of Permatex Blue on the cover, then align the gasket and apply a small weight, keep it on a flat surface (your glass coffee table will work provided your Wife doesn't catch you putting car parts on it). The kitchen counter is another good spot, you just want a good flat surface to establish the gasket bond in a coplanar fashion.

Let it set up about 30 minutes, then install making sure the machined differential casting is completely clean and free of old gasket material. You don't want to see any Permatex squeeze out between the gasket and cover, if there is you've installed too much, clean it off to avoid contamination of the differential.

Do not apply lubricant to the gasket, that's common practice on oil filters to compensate for sliding friction as they are tightened, and prevents seal distortion, but it doesn't apply to this style of seal.

Torque the cover bolts in a crossing pattern, I'm guessing to around 14 to 18 lb ft, but verify that with a reliable source.

Re: Non-H2 stupid technical question
 

Actually it is a good idea to use friction modifiers in all type diffs as it helps the fluid run cooler. This information comes from redline. It does not harm, in any way, diffs that do not require it such as the H2 .

Re: Non-H2 stupid technical question
 

GMs literature (as well as infrom automotiveforums.com) specifically say in Capital letter to NOT use friction modifier in these axles. I know there's debate over it.

Re: Non-H2 stupid technical question
 

Is that for the Burb or H2? Also, does it have limited slip, locking diff or open (like the H2 has)?

Re: Non-H2 stupid technical question
 

co hummer - just use the gasket by itself and you will be fine. If you want to use one of the many gasket "sealers" along with the gasket you can but dont need too. I wouldnt use gasket "maker" with your paper gasket. Tighten the studs in a cross pattern and torque to specs if you really want to be perfect. doug

Re: Non-H2 stupid technical question
 

Gorilla Glue.:giggling: