The NP231 is supported in many applications with almost all kinds of ATF. Any GM, Ford, or Chrysler product will do including modern D/M and ATF+4. Its lubrication requirements are quite simple and it has no cooling abilities, so the best stuff you can run in it is a light synthetic. 5w30 works quite well actually

 

The extremely thick Transmission Fix is absolute ****. Avoid. Some guys here reported quality issues with their gear oil. However the transmission conditioner generally is favorable, but that's hearsay.

 

DOT-3
Conventional Green Antifreeze , 4.0L should use a coolant with silicates and phospates.
Quaker State Defy 10w-30 , this oil is a perfect match for the 4.0L
DEX III for the AW-4 , ATF+4 or DEX III for the T-case
80w-90 Valvoline or Castrol Hypoid gear oil for Front and Rear diffs

 

One thing I can add is to use the same ATF in your TC as you use in your tranny. This reduces inventory and avoids mix up when servicng these components. The Owner's Manual states to use Dexron III/Mercon) in both your tranny and your TC.

Another is the Owner's Manual states to use DOT 3 brake fluid. If you have front disc brakes and drum rear brakes this is what you need. Don't use DOT 4.

 

I remember reading in JEEP Magazine years ago how the only additive they found to be of any good use in a AW4 is Lucas NoSlipStopLeak Tranns Additive. I have used it in quite a few AW4s, four or five of my own, and think they are right. Lucas NoSlipStopLeak. Its all Lucas used to offer for a auto, except their ATF Fluid. Now they have 3 or 4 Auto tranns additives. The NoSlipStopLeak is the thick, Dark Red stuff in the miniature looking gear oil bottle.

 

What About Motor Oil selection? Isnt any 1 going to ask about that?

 

Bobistheoilguy.com -----> Motor Oil University

ASAP

 

Why can't you use DOT4 in an old DOT3 system? That sounds like the old myth that you can't use synthetic motor oil in an old engine.

 

trollolol

 

Use what you want. Don't ask me "Why can't you use". The Owners Manual says to use DOT 3. I'm not going to dick around trying to figure out why.

If you read the labels on the DOT products at the stores you'll see that DOT 3 is used for vehicles with front disc and rear drum, and DOT 4 for discs all around.

 

You're $hit'n us aren't you.

 

LOL I see. I was going to say, it doesn't stop people from dickin around with 15W-40 diesel oil in the engine when the manual specs 30-grade oils.

 

I use T6 5W-40. I got the 5W part correct anyway.

LOL

 

4 is almost 100% backwards compatible with 3. Almost.
4 has slightly higher viscosity and contains borate esters to increase it's boiling point. For most vehicles it's entirely compatible. In some very limited circumstances those additional additives are incompatible with hardware designed for 3. Since 4 did not exist when they were built, you'll find no warnings telling you which system is which. It's assumed you'll use the fluids the manufacturer called out.


Lucas trans fix....here's what Jeep Magazine actually said:
http://www.jpmagazine.com/techarticl...#ixzz2ZeAHrvu8

Note they used it in trans' that were already slipping, not AW4's in good operating condition. The stuff raises the line pressure through the roof and can buy time in a failing transmission. Can't think of any positive purpose for it in one that's operating properly.

 

Engine/filter- mobile 1 10w30
Trans: dex/merc
Transfer case: dex/merc
Front rear diff : amsoil severe gear 75w90