Possible lockup torque converter problem
Thread Starter
3rd Gear
Joined: Jan 2010
Posts: 3
Likes: 0
Possible lockup torque converter problem
Hi, I think I might have a problem with my lockup torque converter on my 87 vette. If anyone has any other ideas or suggestings on easy ways to possibly fix, or if you think the problem might be something else let me know.
soooo
I have noticed every now and then for a while after driving my Corvette, I will park in a parking lot for example, come back out after a few minutes, car starts up fine but as soon as I place it in reverse it dies right away. I can feel the power is there but it chokes out as soon as it hits reverse. I have to keep starting it and putting in in reverse while it dies and inches back out of the space several times. Usually when I am backed out, it doesn't seem to have a problem going into drive then. I am thinking my torque converter locks up and for some reason doesn't release when I stop the car. I never have this problem when the car sits for a longer period of time, then I can always put it in reverse just fine. Its always right after I have been driving it around for a little bit. If anyone knows if treating the transmission fluid or any other tricks might get it to release when it is supposed to I would really appreciate it, because its really annoying and im tired of looking like a fool when I need to back out of parking spots.
Thanks
soooo
I have noticed every now and then for a while after driving my Corvette, I will park in a parking lot for example, come back out after a few minutes, car starts up fine but as soon as I place it in reverse it dies right away. I can feel the power is there but it chokes out as soon as it hits reverse. I have to keep starting it and putting in in reverse while it dies and inches back out of the space several times. Usually when I am backed out, it doesn't seem to have a problem going into drive then. I am thinking my torque converter locks up and for some reason doesn't release when I stop the car. I never have this problem when the car sits for a longer period of time, then I can always put it in reverse just fine. Its always right after I have been driving it around for a little bit. If anyone knows if treating the transmission fluid or any other tricks might get it to release when it is supposed to I would really appreciate it, because its really annoying and im tired of looking like a fool when I need to back out of parking spots.
Thanks
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
It'll stall if it's staying locked up when you stop so it's not doing that. I'd see what the Park/Neutral signal is. If it's seeing Neutral/Park, it won't compensate for the load. I'd suspect an intermittent switch or bad ECM, but I'd want to scan it first.
Thread Starter
3rd Gear
Joined: Jan 2010
Posts: 3
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I guess that would be a cheaper fix if that's only what it is. It seems to be doing it more and more now days in reverse. Every once in a while it will stall out when I start it up again from park into drive, but that is rare. The strange thing is that if its a switch, I don't know why it never happens on a cold start up and then put into reverse. I back out of my driveway and it never happens there on a cold start. Its always after I have been driving it earlier. If it sits long enough it will be ok again. Again no problems when driving at low speeds or stops when the car is still running. Just when I shut it off and come back. Sometimes giving it more gas prevents the stall but that is not very safe in a parking lot.
Pro
Joined: Nov 2005
Posts: 602
Likes: 0
From: North Bay Ontario
A couple of thoughts...if you have your foot on the brake the switch - this unlocks the TC should keep the TC unlocked whether the engine is at operating temp or not. If the switch at the brake pedal is not keeping it unlocked - it might be this switch. Interesting that you say this only happens when the engine is warm because when it has not yet reached operating temp, the TC does not lock up - brake switch on or not.
Thread Starter
3rd Gear
Joined: Jan 2010
Posts: 3
Likes: 0
Yeah that is why if its a switch, I don't understand why it never happens on cold starts. I think it seems to happen more in reverse also because I guess there is one normal idle speed and torque for reverse compared to however the car is set to shift into drive. Its a little above my head...
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
It's not that complicated. The ECM needs to know if it's in gear to add a dash of fuel/air to keep it from stalling. A simple on/off switch is in the console to relay this info and it does it by sliding a couple of contacts together which completes the ECM signal to ground when in Park or Neutral. When that happens, the ECM senses 0 volts so if you were to put a voltimeter on the Pinout (B10 if I remember right), that's what you should see in Park/Neutral and in any other position, you should get the reference or system voltage. Those contacts have to meet up - or give it up - over the range of PRNDL, so that's why you may have a problem in reverse, but not in Drive. If you can scan it, you'll see what the ECM is seeing and if it's positive for Park/Neutral when you shift it into reverse (or drive), that's probably a worn out/misadjusted switch. You could also disable it and see what happens though you should start it up first. Finally, wriggling the shifter around or moving it through it's range a couple of times before you start it (and then starting it) might reveal the intermittent; particularly if it (then) doesn't stall when you shift it into reverse. OR, start it in neutral and see what happens when you shift it.
