Stalling/Slipping=Bad Torque Converter?

'87XJ 267k miles. I don't know if my tranny has ever been rebuilt. I've have the jeep for 2 years and the tranny has been fine. I've changed the fluid one time, but I didn't remove the pan, just drained it. The fluid was nice and red and smelled fine.

Three days ago I hopped in my jeep started it up and put it in reverse, as I backed out of my parking spot I thought I felt the tranny slip. I thought "That's strange.. maybe my imagination" When I put it into drive, I blipped the throttle to see if I could make it slip, and the engine just stalled. It cranked right back up and I went on my way.
Later that same day, at around 45mph the tranny started shuttering real, bad, I couldn't tell if the TC as locking and unlocking rapidly or if it was actually slipping. I shifted it into 3rd manually then back into drive and it stopped shuttering.

Well tonight it stalled on me twice once when backing out of a parking spot, and putting it in drive, the next time I pulled into a parking lot and applied the brakes and it stalled.

Every time this has occurred my Jeep has been warm, and recently driven.

I do have a part jeep I can source a TC, complete transmission, or TCU from if need be.. Just need to narrow the problem down. Right now I'm thinking the torque converter is giving up? Its slipping sometimes, and other times not unlocking properly and causing the engine to stall..
I'm looking for someone to confirm that I'm on the right track..

I have had slipping and intermittent engagement happen when I was low on fluid. I know you just changed it, but did you follow the proper steps to check fluid level? Transmission at operating temp, idling on a level surface, shift from park to lowest gear, pausing for 2 seconds in each gear and then back to park, then pull the dipstick and check it.

My fluid level seemed fine but I knew I had lost some when I pulled the T-case out, so I threw another quart or so in it and it's been good ever since.

Otherwise, all of the slipping transmissions I've had or heard of have been bad clutch packs in the transmission. Which means you'd be looking at a rebuild (or buying a used one would be cheaper). Haven't heard of a bad torque converter firsthand but that certainly doesn't mean it can't happen.

I'll check my fluid again tomorrow.. I might go ahead and change the filter and fluid... Ive noticed more heading coming from the transmission lately. I have a herculined floor I can feel the tranny tunnel getting hot..

pretty sure there is a separate servo for the torque converter lockup and it might be bad....or its coming apart on the inside. ive seen that happen before but there were different problems than the ones u describe...could the white switch connected to the brake pedal have something to do with it? someone else will know more but the servos are pretty easy to change and i think you can even check the resistance in them .

I'm not sure if it's brake switch related because the when I exepierence the shudders I wasn't using the brake.. I know that doesn't rule it out, but probably makes it less likely..

i was having problems with the converter locking up on my 90 and adjusting that switch cured it all.....just throwing it out there...never know with these dinosaurs

So adjust the brake switch to make it less sensitive?

can you explain a bit more about this "white" switch? are you talking about the plastic switch that has the hose connected to it? i have/had that switch on my 89 with the bendix anti lock system. i replaced the system with a 95 booster/master, and pedal assembly. i used the 95 brake light switch and spliced it into my stock wiring, but did nothing with that white plastic switch yet. brakes work great, but have allways had trans problems. could this white switch have something to do with it? mine has a lag between shift points, and a bad whine in all gears. park and neutral has no whine. i figured a bad torque converter or pump aswell.

Well, if the fluid is at the correct level, good condition, and the correct kind--Dex III, then you should adjust the throttle pressure cable: http://naxja.org/forum/showthread.php?t=1015963.

With that done, time to determine if the problem is mechanical/hydraulic or electrical in nature.

Unplug the TCU, or pull the 10 amp inline fuse, then drive the vehicle shifting manually. You will get 1st in 1-2; 3rd in 3; 4th in D; reverse, neutral, and park. If you don't get that EXACT result you have a mechanical/hydraulic issue. If you do get correct shifting manually, then the problem is electrical.

If the problem is electrical then you need to check: TPS bad; TPS needs adjustment; TCU; TCU fuse; solenoids; brake switch; and the solenoids.

that switch only disengages the torque converter when brakes are depressed....or if not adjusted properly it will not tell the converter to lock at all which was my problem.

I just took a look at my switch, I see where there is supposed to be a rubber hose but there is none. I only have the electrical connector connected. What is the purpose of the rubber hose? ( I have no cruise..)

Its for the cruise, ignore it.

Ok, I'm adjusting the switch in to make it more sensitive. I had to completely remove the switch and braket to adjust it, the switch wouldn't screw in because the body of the switch was hitting the pedal assembly bracket. I double checked my fluid level and its spot on..

I played with the switch some, my initial readjustment was out too far and the TC wouldn't lock. I have it back in adjustment again. This is a sucky problem to troubleshoot because its intermittent. I may think I have it fixed, and a couple days later it crop up again. That's why disabling the TCU isn't really an option.

Well it acted up badly on the way home from lunch today, almost stalled in the parking lot then did T/C unlock/lock, unlock/lock shutter. So when I got home I pulled the 75amp "Trans" fuse. Drove it back to work.. I did not have to shift it manually.. is still shifted on its own, I guess the TV cable is a fail safe? Also.. I think my T/C was still locking up as normal. The only difference that I noticed was that the light in my "power/comfort" switch was out..

Maybe there is another fuse I need to pull? Where is this 10amp inline fuse?

pretty much right above the passengers knees between the lower dash plate and the heater box....should be a pig tail with a fuse in it and u might hafta dig around a lil to find it

stephenspann27 said:

Well it acted up badly on the way home from lunch today, almost stalled in the parking lot then did T/C unlock/lock, unlock/lock shutter. So when I got home I pulled the 75amp "Trans" fuse. Drove it back to work.. I did not have to shift it manually.. is still shifted on its own, I guess the TV cable is a fail safe? Also.. I think my T/C was still locking up as normal. The only difference that I noticed was that the light in my "power/comfort" switch was out..

Maybe there is another fuse I need to pull? Where is this 10amp inline fuse?

Click to expand...

It's a 7.5 amp fuse - if you have a 75 amp trans fuse I don't know what exactly it is! That fuse, iirc, only controls the reverse lights and the NSS or something like that.

The fuse you want is the one 90 waggy mentioned. If you can't find it, just unplug the connector from the TCU itself, which is mounted to the back of the lower half of the dashboard above the passenger's feet.

7.5* Your right. I guess I'll throw that back in and look for the real deal.
Thanks.

*update*
I drove around last night and this morning with the TCU disabled. I didn't have any issue until around lunch time today. I was pulling into my parking spot and it died. I went and and worked an hour then got back in the heep to go to lunch. I thought "well if it died with the fuse unplugged, I might as well put the fuse back." I put the fuse back in started it up, and backed out of my spot and it died.. it died three more times on the way home. It happens when slowing for a 90 degree turn, or doing a right on red etc. It also did the "shudder" thing at 45ish mph.

I highly suspect the TPS. I have a j-yard TPS that I put on tonight, but for whatever reason, with the j-yard TPS installed and adjusted my jeep stalls off idle. So I had to reinstall my original TPS. Basically I dont' have a good spare TPS to swap in.. so I might have to buy one.

Kinda funny story.. when I was adjusting my TPS the values were totally off. i was getting like .3vots instead of 4 or 5.. after 20 minutes I remembered i had once again removed the TCU fuse. I stuck it back in and my #'s went back up to normal.

When talking with a coworker today, he was trying to convince me that I have a problem with my engine and not my trans.. which I'm not ruling out..
He told me about his Honda mini van that had a bad ignition switch, he said if the mini van stalled at hwy speed, it would restart its self like a vehicle with a manual clutch would. He said when this happened it would cause the van to buck like it had a trans issue. Is that really possible?

Well it looks like my co worker is right. I installed a new TPS today and test drove. This time the symptoms were a bit worse and I am now pretty sure the problem is engine related. So.. now I'm thinking maybe fuel pressure problem? I already replaced the coil.. maybe bad CPS?