Rear diff fluid change
 

How many quarts and what weight should i use in my rear end

http://www.ls1info.com/article.php?sid=214

There ya go.

I would run a strait 140wt. myself, and not a full synthetic either.

For whatever reason, I know that everyone on this site is building their vechicles to make MO power. So why not step up to an oil with a higher film pressure strength? It only makes sense... I have been in the business for quite sometime now, and have built thousands of differentials, hundreds of 7.5-7.6" f-body diffs to be more specific, and I wont let anything roll out the door with less than a 140wt. oil. I mean it is a 7.5-7.6" diff, and we all know how weak it really is......help it out a little would ya!

The thin welter weight 75-90 oils just dont cut it. Same for a synthetic under an ISO 1000 140wt rating. I myself run an ISO 1000 250wt. oil in my differentials.

http://www.schaefferoil.com/data/209.html some data....

Venomcure98, you live in Ok right? I KNOW it gets hot there, but does it ever freeze where you live? If not, I would recommend a minimum of a 90-140wt. Just to help the diff live a little longer.

2 qts. oil, 1 bottle of friction modifier.

YA it freezes here. man it can get nippy thanks for the adivice u are a reall help man:)