Hey everyone.. First off, happy holidays everyone. Secondly, I've been searching the forum all day because I'd like to try changing my transmission fluid.. 98 tj 4.0 manual..am I dopey cuz I see that u can use motor oil in the tranny.. I also see a few people suggest redline mt-90.. But i also see atf+4.. Which one is it?
And then what about the transfer case? Should I change the fluid there too at the same time? And where the heck is the tc?all of a sudden I'm confused! The problem is I'm having a real hard time shifting into 1st at a stop as the engine gets warm. Please help! Thanks and sorry for the ling write up

AX-15 uses MT-90
ATF+4 goes into the transfer case

heres a good write up
http://www.4x4xplor.com/trannyservice.html

Or 10/30 synthetic motor oil in the transmission.

I put royal purple syncromax in mine and their atf fluid in the transfer case, kind of expensive tho but worth the money

second that I am changing mine this weekend and you cant go wrong w/ royal purple never fails

Heck yeah, peace of mind knowing you have good fluids to handle the abuse you're going to throw at it

royal purple from what ive heard is actually market hype and no better than most other less expensive synthetics, if you want peace of mind use AMSOIL lubes.

Royal Purple Synchromax is indeed a good transmission lube for the NV3550 used starting in 2000 but I'm not so sure it's suitable for the OP's '98 TJ that uses the AX-15 or the similar AX-5. Or, Royal Purple's or Amsoil's 75W-90 gear lube would work too. While both of those are GL-5 gear lubes and GL-5 gear lubes are normally too harsh for use inside either transmission, those two in particular are a different formulation of GL-5 that will not harm the synchros like a conventional GL-5 will.

For the OP's AX-15, I personally would use either Redline MT-90 or a synthetic 10W-30.

I've always had good experiences with it. Granted i wouldnt shell out the money for the motor oil but the gear and trans oil is pretty good. After changing mine i noticed it was a little smoother leaving from a dead stop

Thanks everyone. I've been pouring over all the threads and I feel like I can tackle changing my tranny fluid instead of paying thru the nose at a garage. Should I change the transfer case fluid at the same time? Or does it not matter?

It doesnt really matter if its at the same time or not, but while you're under there you mine as well do it. its easy to do and wont take much longer. i'm kinda ocd in that sence and like to do it all at the same time, same with the axle fluid. check out this site, see if it helps. Good luck, let me know how it goes!

Jeep NV3550 Transmission & NP231 Transfer Case Service

While ur under there change everything since u already got everything out

Jerry I have a 6spd manual in my 05' is that the same model tranny as mine the NV3550

NV3550 is a 5-speed, your 6-speed is the NGS370.