Originally Posted by caronaxtr

From what I understand you'll want to run ATF+4 for your transfer case.
$6.99/Qt, I bought 3 Qt's you shouldn't need that much

Be sure to get somthing to help you fill your transfer case, you won't be able to just pour it in the fill plug....

Originally Posted by Jesse Hallum

If it is filled with engine oil, Rockland Standard Gear, Inc. recommends using 10w30 synthetic engine oil in all Jeep NV transfer cases instead of ATF, primarily due to excessive misting/venting problems that tend to cause the fluid to dissipate quickly without the owner's knowledge. Chances are, the previous owner did just that, as I did when I owned my 2005 Unlimited. Both TC and transmission in mine were filled with 10w30, and both worked much better because of it. I would imagine the new owner was just as surprised when he performed fluid changes.

If it's filled with gear oil, someone was terribly misinformed. I don't believe I've ever seen anyone put gear oil into a transfer case before.

Originally Posted by CCKen

Here's the Rockland Standard Gear article that talks about using motor oil in the TC, on pages 52/53. They say to use 5W-30 Synthetic oil in the 231/242. Rockland also sells their product for TC's, RSG-530GM. I've read on another forum where the RSG-530GM fluid runs $10 a quart (+ shipping).

RSG article:

http://www.rsgear.com/articles/2002_01.pdf

The OP's TC may have had 5W-30 Syn or RSG-530GM oil in it.

Originally Posted by salad

Excellent link

Originally Posted by CCKen

See my edit in my last post.

Originally Posted by salad

Ah... well still an interesting read LOL.

We should make a meme for that. "What's the best fluid for X?" (5000 responses of what various people use, with no analytical reasoning or comparison)