I recently got a 2000 xj 4.0 needed a motor had 181000 on the body so I put a new motor in it I have been driving it for a month or so now and I'm about to make a big trip. checking fluids and what not looks like my rear diff might have a cover gasket leak so this weekend I was going to replace the gasket what brand gear oil should I put back in it.?

Chrysler 8.25

 

I normally use O'Reilly's 80W90.

 

Yes, 80W90 dino or 75W90 if using syn.

 

I was going to use 75w90 full syn or part syn but I didn't know if there was a good brand or if it really matters like using wal marts super tech or advance auto gear oil or valvaline brand

 

Use the Wally World 75W90 Full Syn stuff. It's fine. Clean that thing out good before refilling. And if you plan on keeping the thing. Buy one of these:

http://www.quadratec.com/products/52416_104.htm

SOOOOO much easier and cleaner.

 

i used the walmart full snythetic in mine front and rear.

 

Thanks.! I was told not to use fancy with jeep figured wal marts would be good from what I see ill need 4 pints . Wal marts brand is around $11 a quart royal purple and lucus are $20 a quart I can pay the difference

 

Hmm I might try it out

 

Wait which fill syn I only see 75-90 in syn blend and full syn 75-140 in full syn