jstieber

I have 99 Cherokee Sport. 134k miles and an auto transmission.

I did a search for this issue and so far have found some sporadic issues with overdrive but none quite like mine.

Literally every other time I start my jeep overdrive works. Its guaranteed every other time. If overdrive works when I'm driving it means that the next time I start my jeep overdrive will not work. On those starts it will shift normally all the way up to 55-60 and then will go into overdrive for about 30 seconds and then shift out. If I shut it off and then restart it shifts into overdrive and stays until the next time i have to start it. I know nothing about transmissions so please don't feel any detail is too small to leave out.

excess650

That just sounds wierd. Fluid level? red or brown? smell like ATF, or burnt?

Have you adjusted the kickdown cable? The adjuster is on the end of the throttle body shaft.

The AW4 trans has its own controller aka TCU that is seperate from the engine controller. The TCU receives signals from the throttle position sensor aka TPS, vehicle speed sensor aka VSS on the tailshaft of the trans, and brake switch which disengages torque converter lockup.

First of all, are you confusing overdrive with lockup? Overdrive is the 4th gear, and lockup is a function of the S3 solenoid activating and stopping the slippage of the torque converter( which drops the rpms by another 200 or so).

Try this: on your next several useages of your Jeep, start in 3 and after you've felt it shift from 1-2-3, move it forward to D and see if you feel it shift. If it does, its gone into 4th (OD), so watch the tach and see if the revs drop another 200 rpm whle maintaining 45+mph. That would indicate lockup.

PM me your email address and I'll send the AW4 mauals as an attachment.

jronald

I had the 46RH that did simular, I could coax it into OD/Lock up by fiddling with the towing button. I swapped the filter and transfluid, added some Lucas and it does fine now....about 10k miles ago. Has almost 200k on it total.

YMMV but its worth a try
Ron

SeriousOffroad

The torque converter lock-up voltage goes through the brake light switch.

Next time it happens maintain your speed and using your left foot, lift the brake pedal. If the RPM's stop fluctuating you've found the problem. All you need to do to fix it is to adjust the brake light switch.

jstieber

I just took it out and tested to see if i was confusing lockup with overdrive. I no nothing about transmissions. It seems that it will shift into 4th/OD. Heres what happened..

I took it out knowing that the last time I drove it I was on a highway maintaining 60mph and the rpms were very close to 2,000. I assumed since its been the common trend that this time my revs would be much higher since I haven't been getting OD or lockup (still working on figuring out the difference). I was right. I did what excess650 did and started in 3 and then shifted into drive. I felt it shift from 1-2, 2-3, and then 3-4. At 60mph my rpms were at 2550 approx. Also while going 60 on this test run I attempted to lift my brake pedal with my left foot but it wouldn't move at all and I was really lifting and my rpms stayed the same. Next I pulled over, shut it off, and started it again about a minute later. I took off again and again felt it shift through every gear up to 4th. This time though at around 45 mph my rpms dropped (I'm assuming this is lockup). I continued to accelerate up to 60mph and my rpms stayed at 2,000. I think I must've been confusing OD and lockup but the difference in my rpms is more than 200.

excess650

It certainly is odd that it happens every other time. It sounds like its not always going into lockup, and that is a function of the S3 solenoid.

You might try adjusting that kickdown cable before you start throwing parts and $ at it.

jstieber

i was hoping beyond hope that there might be a cheap/free fix for it. I bought it with some deer damage just as a temporary vehicle. I'm not putting any more money into because its going for sale in less than a month.

I'll look more into the S3 solenoid and see what I can find. Thanks for your help.

project78

........
...........Does anybody have an answer for this,I have a 2000 I-6,aw4 and it has the identical problem.If I leave for work and if it is not going into overdrive,I pull over,put it into park,turn the key off then on,put it into gear and it is guaranteed to go into overdrive and will continue to go into overdrive until the next time I use it.AND IF IT DOES SHIFT WHEN I THINK IT WOULDN'T IT SHIFTS BACK INTO 3RD UNTIL I PULL OVER AND REPEAT STARTING IT..............It is so predictable...coincidentally my a.c. stopped working at the same time this problem started..