Dan91

Yep...trans started slipping terribly after a fluid/filter change. It likes to come out of gear too, at idle. It's so bad that it's undriveable. So anyways, I'm probably gonna have to buy a new used trans, what years are bolt on for a 1989?

DFlintstone

??I pretty fussy on automatics..coming out of gear, AND slipping. Could they be related/linkage? If it's an 89 you might want to check the TCU fuse near the TCU under your glovebox.

CrawlnCoupe

this is a common thing with automatics according to my trans guy. he told me to only flush a trash if they have under 100k (roughly) on them otherwise you risk it slipping after. i asked him if it was a good idea on my cherokee (138k) and he said he wouldn't risk it.

CrawlnCoupe

it could be worse though, my old 89 had the ba10.

Dan91

Yeah, see I didn't think this'd be an issue because I changed the fluid when I got it (like 3 weeks ago) and it shifted perfectly fine...I wanted to freshen up the fluid a bit more (it was still a dark-brown-red after the first change) I am amazed that it went from shifting perfectly with part new fluid to as bad as it is now after a second change.

Dan91

Going to check now

Edit: Couldnt find it...

CrawlnCoupe

how many miles do you have on it?

Dan91

140k

cruiser54

You didn't look hard enough. Just slide your hand up under the dash on the passenger side and you'll feel the TCU. Pull the harness down and there's a fuse in it. Take the fuse out and clean it /check it for continuity.

Dan91

Will check tomorrow. Anyways, isnt the AW4 supposed to operate in "manual" mode when the TCU fails, so I'd at least get 1st gear reliably if the fuse was blown.

bnkk

This

tjwalker

Also need to know which fluid did you use?

I've seen more than a few incidences of transmission slippage with the addition of ATF+4 fluid. Because of that, I will only use and recommend using Dex/Merc III compatible fluid; widely available anywhere. Dex/Merc is the fluid that the mfg. of the transmission (Asin Warner) recommends.

DFlintstone

Yes, unfortunatly it will still function somewhat, (slipping) without the fuse. I thought of using that for a "security" switch. Thought it might be cute to set mine up so if some (fool), did try to steal it, they might be caught out there reeving the engine not going anywhere!
Just an easy check. Also if fit IS blown that might say something. I don't imagine that could cause the shifter to move into neutral..Idk!

Dan91

The shifter wasn't moving into neutral, just the trans itself will slip into neutral range with any load on it. I'll be checking for this fuse and doing other testing today to rule out any simple problems. Also, I may've been checking the wrong thing for a fuse. There's a large metal box with a Bendix stamp on it under the drivers side dash but I think that might be the ECM now that I think about it. And I vaguely remember my other 89 having the TCU on the pass side...been a long time lol

Dan91

Problem solved, and it was the most ridiculous problem too

On the new filter the boss on the intake seal was about 3/64" (1mm) lower than the old one, and it caused it not to seat properly. If my understanding is correct then the filter acts as a straw for the intake tube, so if the seal isn't good then it's like sipping through a straw that has a hole above the liquid level: it sucks air instead. Long story short, believe it or not, I put the old filter back in and it works great again. Going back tomorrow to return the filter