OEM fluids

My xj didn't come with it's manual and i just swamped my jeep (under water for 24 hours) i'm tried searching and couldn't find what fluid a 90 5 speed (ax-15 right?) and the NP 231 t-case (atf i beleive is what i found searching?)would use for fluid? I found that the diffs take 80/90 but could someone tell me if they know what the tranny and tcase take? or a website i can look it up on? thanks for your help!

I know I put 75w-90 gear lubricant in mine, which says it matches gl-5 on back. I only have 2wd so i dont know about the transfer case. I would imagine its the same though

ok dealerships told me to put GL3 gear lube in the tranny and ATF+3 in the transfer case. Does this sound correct? Also anyone know how much it should take? Appreciate the help.

ok got the info i needed. tranny takes about 3.5 quarts and the trasfer case takes about 1.5 quarts. Hope this thread helps anyone with the same questions I did.

yeah it says in the haynes 3.2 pints...dex or mercon atf.

Do a search, there are several threads about the correct fluid for the AX-15, AX-5 and XFER Case.

GL-5 is a misprint, DO NOT use it, GL-5 fluids contain additives that can become corrosive to the synchros if it gets warm enough.

GL-3 Manual Transmission Fluid is the correct fluid to use. The Syncrhos require some sort of friction modifier, so regular gear oil (NO FRICTION MODIFIER) could cause shifting problems. Besides, most gear oil is GL-4 or GL-5.

People have used Redline MTL and MT90 (thicker version of MTL) which is technically a GL-4 fluid, but it advertises that its additive won't become corrosive to the synchros until triple the temps of regular GL-4 and GL-5 fluids.

ATF for the XFER case. ATF+4 is synthetic ATF, ATF+4 has now been licensed and they now sell it at reduced prices at Walmart and other stores. I have no Idea how well it work, I don't know if anyone has tried it, but I don't think the XFER case are to finicky as to which ATF you use, as long as its ATF. Some people are big endorsers of Synthetic ATF, so maybe ATF+4 might be a cheaper synthetic ATF.

Click the link in my sig, and go to the Tech Archives. Capacities and recommendations are culled from FSMs

And Rick Anderson is correct (and I need to correct it on the site - I blindly copied when I built it...) do not use GL-5 in the AX-15! GL-3 is preferred, GL-4 is tolerated.

GL-5 contains added sulphur as an EP lubricant, and sulphur is antagonistic to copper-based alloys (like the bronze synchroniser rings in the AX-15.)

Nearly any transmission fluid can be used in the transfer case - it's just a lubricant that is circulated by a small mechanical pump. You'll starve it for oil if you go with gear lube, but you can use any Dexron II/III (natural or synthetic,) ATF +3, or ATF +4 - whatever is more convenient. And, you can use either natural or synthetic fluids in there - there are no clutches to give you trouble

Questions like this are why I got the Tech Archives going on my site - sort of a "one-stop shop" for Jeep tech. Specifications are added as I collect FSMs - but I have discontinuous coverage from 1962 (or so) to 2001. Gotta get more books...:rtm:

5-90 said:

... there are no clutches to give you trouble...

Click to expand...

? Then why is ATF recommended and Plain Gear Lube is bad?

ATF is for transmissions with friction surfaces, like clutches and bands. The only thing I can think, is the XFER Case Pump looks just like an Automatic Transmission (ATX) Pump. Does that pump work much better with ATF, that is why its recommended over regular gear lube?

Theres also sun/planet gears like a ATX, maybe ATF is formulated to better lube those types of gears.

Incase anybody with an auto trans wanders into this thread -

USE DEXRON 3 in your auto.....don't use ATF!

HOWEVER......the transfrer case can use dexron or ATF.......it's just to lubricate in there, that's all.