aw4 torque converter issues
 

alright the transmission has 115k on it, the tcm is orginal so it has 210k on it.


the issues is.... when the torque converter has locked in it will not unlock sometimes when i let off the gas pedal unless i tap the brake pedal. sometimes it will unlock when i let off the gas pedal as it is supposed too. the fluid was changed when i put this transmission in 15k ago. the filter looked good so it did not get changed. the fluid is full and clean. now i believe their is a lockup solenoid am i correct? i think this could possibly be an electrical issue, as the transmission shifts fine. i will have to have my codes scanned and see if anything new has come up.

thanks for the help.

TPS is a suspect here.

As Cruiser said, check the TPS. The TCC is operated by a solenoid, driven by the TCU. TPS is one of the main sensors it relies on to know what the accelerator is doing.

hmm. ok i new it was controlled by a lock up solenoid i just didnt know that it was engine sensors too. learn something new every day. specifically how do i need to check the tps? do the regular resistance check.

other than this issue the jeep drives fine.

The TPS signal is fed to the PCM and the TCU, they both use it.

There are three wires on the TPS connector....ground, +5v power, and signal output.
Measure the signal output voltage, it's the center wire in the plug. Orange wire with a blue tracer, IIRC.
You'll have to do this by backprobing the connector while it's plugged in, or using a small pin to pierce the insulation. Key ON, engine OFF.
It should start off very low and increase smoothly as you open the throttle, with no skipping, jumping or dead spots.
And old-fashioned analog voltmeter with the moving needle is excellent for this. Should see a smooth sweep from <1V to just under 5V.

Specs are 0.26v at closed throttle to 4.49v at WOT.
The exact values are not critical for TCC lockup purposes, the TCU looks for a relative decrease, indicating you've taken your foot off the accelerator, or an increase when you step on the gas.

dont have my multimeter at home, will check that stuff at work. but today i unplugged the tps checked the connections, readjusted the kickdown cable and testdrove it. no issues so far. but it will not surprise me if it does it again. would changing the filter and trans fluid help maybe? or does this seem to be an electrical issue?

I have posted elsewhere on here but am stumped with an AW4 not shifting to OD at times. I have 302k on an XJ98. Did the tranny fluid (not flush) about 5k ago. Few weeks ago I had the CEL (P0700, P0740, P0743) and the car started behaving (limping). I replaced the TPS, cleared the code, and everything was fine for about 100 miles. Codes 0700 and 0743 came back. I adjusted the tv cable, cleared the codes and everything was fine for another 100 miles. Same 2 codes came back. I did nothing, just cleared the codes and it now drives fine. Probably for another 100 miles... Do you think it could come from a bad (the new one) TPS, TCU? I think I checked the solenoids (at the TCU harness) and it checked ok (within 11-15 ohms). Not sure since I am not too bright with electrical stuff. I still have to clean the NSS although not sure this could have an impact. I just don't understand how just clearing the code would make the transmission shift just fine.
Thanks for your help. This forum is outstanding.

the code will throw it into limp mode, once cleared the trans will behave normally until there is another occurence. my original trans did this once and it sucked having to drive 45 miles down the hwy with no OD. it could be a bad OD shift solenoid on yours.

That's what I would like to test for without taking the pan down but I am not sure I did it correctly. Couldn't find a diagram with the instructions for the 98.

well the code needs to be active and you can check the solenoids with out dropping the pan, their are two plugs coming from the transmission on the passenger side of the firewall i believe you need the black connector. i do not know the pin numbers that you need though.

just a suggestion you might be able to get better help if you start youre own thread.

Got it. Thank you!

The solenoids fail in two different ways, electrically or mechanically. When you measure the resistance, you are verifying the coil that operates the solenoid is more or less intact.
That does NOT tell you if the solenoid is worn or sticking mechanically, which they can do.
You can swap it with another to see if the problem moves.

Thank you. Didn't realize that about the testing of the solenoids. Next time the CEL comes on I'll have to try that. I am assuming I would go first with the TCC solenoid (vs the 2 shift solenoid)?

which might be what mine is doing, on the 30 mile drive to and from work i had no issues. im thinking a flush might be a good idea.

NOT a flush, but maybe a few changes in succession?