paulisawesomer

So replaced the exhaust manifold, muffler, full tune up, replaced all fluids and this machine ran perfect for 1000+ miles. So, packed up for a road trip and 400 miles in, the trans shifts out of OD and into 4th. So I can step on the gas and it will kick back down to OD but as soon as I let off the gas or there was load on the engine, it kicked back into 4th. Same on a hill, it would go into OD, get to the top of the hill and it would drop into 4th. Then, say 100 miles later, would just go back into OD. If I stopped for gas or whatever, it would run perfect for 50, 100, 200 miles and then act up again. Help please I'm 800 miles from home, although I have a garage to work in and half my tools with me I think. Luckily I'm staying with family.

paulisawesomer

PS, i have limited internet access, i'm borrowing some wireless from some neighbor, so if i don't reply to any suggestions right away, that's why. And it's a 96 4.0.

mrfajita

AW4 is a 4 speed (3 speed with overdrive) so it is kicking down into 3rd. The electronic kickdown may be messing up on you but beyond that, I don't know. As long as your overdrive does indeed work though along with the other gears, it isn't anything mechanical. You Transmission control unit may be getting screwy (which on XJs is thankfully a separate unit from the ECU)

paulisawesomer

So is that the transmission control module, the big thing under the dash? I would need to go to a dealer to get that checked or is there a way to check it some other way? Autozone checked the codes and found nothing on odb but there is some other drb that I think only dealer can do.

paulisawesomer

And if anyone is still out there...can I use a Transmission control unit/module from another jeep or does it have to be the same year? I'm assuming they are interchangeable if they are all the same trans/engines.

Also, as far as scanning codes, do I need to go to the dealer to get the full scan done or can i get special jeep/chrysler cards for scanners that are specific to jeeps. Manual says something about DRB codes and it looks like those are jeep specific. Not sure if that is just another word for the ODB codes either. Regardless, not getting anything via ODB or key off on etc way either.

98jeepsrt6

Try adjusting your kick down cable.. Its is on the throttle body.. Looks like a throttle cable.. You should have three.. Nearest to TB is the Skinny pedal.. The one in the middle is the Cruise Control.. and the furthest from TB is your kick down cable..

Theres a lil button on there.. With engine off open TB butterfly all the way open.. The press the button and u will see the cable slide back a lil.. see what happens afterwards..

For reading the codes, any auto store will do it for free. Just go in tell them you need to check what your CEL is saying.

Do you have the Check Engine light on??

98jeepsrt6

This would be your kick down

paulisawesomer

No check engine lights on, but service manual says to do a DRB scan. This is the factory manual, so just following their advice. Dude at Autozone said that the dealer would have either better scanning tools. I know there are a few sensors too, so I was wondering if it was just one of those too. I'll try the cable today. thanks

paulisawesomer

And here's what I was referring to....

cleburnecherokee

I too seem to be having this issue the past few days, I will be doing 55 or so and the engine seems to be revving unusually high, then out of the blue it will shift to OD on its own, then a few miles later, back down to 3, then back to OD.... seems to have a mind of it's own.... will also check the kick down cable as suggested, I had thought of that actually but just didn't realize there was an adjustment on it.....

-Andy

freegdr

tcm/tcu search the forum here for transmission control module

Bassman4461

If he has an AW4, the cable your showing him is actually the TV cable and does not control shift points.The AW4 shift points are controlled by the tcu that is monitoring the TPS and Speed sensor.Also the brake light switch will unlock the converter when the pedal is depressed.Kickdown for this particular trans is controlled by the TCU,not the TV cable like the old TH350/400,or the old Ford C6.I had recent issues with my AW4,and after testing the sensors, found my TPS had intermittent failure.Replaced TPS, problem solved.
(Tv cable controls pump pressure for firmer or softer shifting)

tj40

I think you can unplug the tcu for sure and manually shift til you get home........

paulisawesomer

Thanks for all the posts, I was thinking about the TPS because everyone keeps talking about it and it seems to fix a whole bunch of issues. I think it's about 30$ , so I'll try that first and see what happens. Much more frequent now and it's 20 degress in chicago on a good day. I'll keep you posted and I did make it home OK......

anyone ever visiting Illinois, I-80/88 coming into illinois is the absolute worst drive ever. Except for I-65 in Indiana, sorry if anyone is from there. 2 worst routes ever, flat, ugly and boring.

paulisawesomer

One more note, adjusting the cable partially fixed my cruise control....gotta love it. now it works when it feels like it instead of not at all.