steelybill

My '94 Cherokee has 156,000 miles on it. I have had it only about 5 weeks. I'm wondering about changing the oil in the transmission, at this high mileage, since I don't know if or when it was ever changed.

As some of you here already know, changing oil in a hi-miler can lead to failure of the transmission, when the new oil cleans the varnish etc out of it.

Any words of wisdom on the Jeep transmission in this regard ??

Dumajones

this is for the AW4 automatic, if you have auto?.
A few good drain and refills with DEX III/MERC ATF should do. Just drain old fluid, refill drive for about 10-15 mins drain, refill again. Do this about three or four more times or untill the fluid looks nice clean red ATF. The filter will not need changing. Read this thread up to post #23 on doing the AW4 drain and refill.

this thread>>> https://www.cherokeeforum.com/f2/aw4-drain-fill-198634/

steelybill

The reason I asked about this, is that the GM transmissions with high mileage on them, without ever having the oil changed, can sometimes go into self destruct mode if the oil is changed, and cleans all the old crap out of them.

I just don't need the experience of a rebuild on a Jeep AW4 transmission, even though I've done a bunch of the GM types, and even Borg Warners in the old days...
The thread you mentioned didn't anything much about this..unless these transmissions are "indestructable"

Bill

Dumajones

Well I can tell you this, yes the AW4 is dam near indestructible. Ive never had issues doing fluid change on a high mileage AW4 doing the drain and refill way. But I have heard stories of ppl having their trans force flushed, that knocks stuff loose and caused problems. But that was stories, I don't know Ive never done the force flush. You will be fine, just remember to use DEXIII/MERC.

If I'm wrong with any of this stuff I'm sure someone will post and set me straight. lol

BlueRidgeMark

If there is oil in your transmission, you have a huge problem.

The correct stuff is Dex III/Merc transmission fluid.

Not oil.

My trans had fluid that looked like well-used engine oil, and smelled burnt. It started slipping on me very badly one evening, to the point where I almost had it towed. I limped it home.

I did a fluid replacement about 15,000 miles ago, and it's been fine ever since.

Of course, if I put oil in it, I would probably have ruined it.

cruiser54

The AW4 is probably one of the best, if not the best, auto trans ever built in the world.

It's not a POS trans like Ford, GM, or Chrysler.

Drain and fill only. There is not even a factory recommended interval to change the permanent screen in it either. It's not a filter.

Only use Dex/Merc III fluid. Nothing else.

kgm

Yup, drained nasty black burnt fluid out of my AW4 at 155K, and its running smooth at 170K now. Drain it out! I just did it 3 times then at every oil change and now its nice & red.

cruiser54

It's sooooooo simple and many try to make it complicated.

Fred/N0AZZ

As long as it doesn't smell burnt just drain and refill a few times. My fluid looked terrible when I bought it at 228,000 so I dropped the pan and replaced the screen after the first drain and refill. After the second round it has looked great ever since and worked flawlessly.