Hoping it just needs new fluid

[BrokenSockets]

96 XJ 4.0 AW4 242

Hey guys, I am having a transmission issue with the AW4.

I was towing a trailer uphill on the highway one day last week and had RPMs at about 4k at 45 mph. Pulled off the highway and could smell burnt trans fluid. It looked black, smelled burnt, and a lot runnier than normal. Shifting very late, jerky while stopped and in gear. I had no choice but to limp it home on the back roads (couple hundred miles.)

I have a good AW4 in my parts jeep but didn't feel like digging it out of the snow at -30.

After I got home I noticed I have a major leak at the downpipe flange - broken bolts probably from several stuck-in-snowdrift excursions (and that's just in my driveway at the farm.) The exhaust look like it was blowing directly onto the transmission. I was waiting at a warehouse out of town and idling for about an hour the day before. Wondering if I killed the fluid with the heat and that alone could be all the trouble.

I am going to pull the pan, change the filter, and do a full flush through the cooler lines until it runs clean tonight. What are the chances that I may have done some damage driving it with bad fluid and is there anything to look for with the pan off - or should I just do filter and fluid and see what happens?

 

[donthelegend]

Heat kills automatic transmissions, but AW-4s are pretty resilient. Start with just changing the fluid and see how it is after that.

Although a "couple hundred miles" of overheating the transmission very well might have killed it.

 

[Jeepguy03]

Heat kills automatic transmissions, but AW-4s are pretty resilient. Start with just changing the fluid and see how it is after that.

Although a "couple hundred miles" of overheating the transmission very well might have killed it.

+1

I'd start with just the fluid. The filter is just a mesh screen so it won't really filter much. Do a couple drain and fills to get all of the old nasty fluid out and see what it does.

 

[cpefy3]

I am in full agreement with the idea of changing the fluid (dex/merc III) and filter. Be careful not to over tighten the trans pan bolts. But, your symptoms sound very similar to those of a clogged transmission breather valve. I thinks this may also have caused the premature wear of your transmission fluid. Just a thought...

 

[ParadiseXJ]

When was the last time you changed the fluid? Do you think that this one event is what burned your fluid (has it been nice and cherry red up to this point) or do you think this has happened over a period of time?



As you can see, temperature and time make the difference with tranny fluid. Under normal circumstances, just regular driving, the fluid should be changed at 30K intervals. With extreme conditions like towing, wheeling, slow n' go etc. you can cut that in half (15K)

If you don't already have an auxiliary tranny cooler (other than the radiator circuit and the tiny stock cooler in front of the condenser) you should have one for towing. Also handy is a tranny temp gauge to let you know how hot the tranny is getting so you can pull over to let it cool off when necessary.

Just like the others said do a couple drain & fills over a couple hundred miles and see what happens. I ran my AW4 almost dry at extreme temps for a couple days. That was about 25K miles ago.