lockup solenoid?

[arvetus]

Has anyone had a problem with a lockup solenoid. I have a 91 regal sedan with a 3.1 MFI. Not sure of the tranny model, but it has "overdrive." I don't have a problem with it stalling out at a stop, but I have a problem when driving at a constant freeway speed with it shifting in and out of "overdrive." Thought the problem was possibly related to the rear brakes being the kind that freeze up constantly, but at this point, I'm not sure. Have 2 new calipers/rotors and everything and still get the same thing. When the car is driving normally and I touch the brake, it will down-shift out of "overdrive." Think it could be the lockup solenoid?

[Guest]

The solenoid started acting up in my Cutlass, but it was the ECM doing it, not the solenoid. It is a 2.8L with the auto. For the 3100, I don't know seeing that there is a differant ECM for those cars.

 

Taylor

[arvetus]

did you have replace the ecm? or was just it a simple grounding problem?

[Guest]

I had had to replace the ECM. As soon as I did that (just swapped out the MEM-CAL) it worked fine. The Solenoid still gets a little flakey on me every now and then, but what do you expect when you got a car with 312,000 miles on it? I am going to replace the solenoid when I do to put the new motor in.

 

Taylor

[god910]

When you are driving and you hit the brake it is not downshifting it is unlocking the TCC. If you hit the brake and the TCC didn't unlock then the car would die as the engine would slow down as the tranny did, because the two are locked together. The touchyness of it shifting in/out of O/D could be due to a mal-adjusted Throttle valve cable. I have seen it before but mainly on 700 and 200-R4. HTH.

[arvetus]

I don't know if this helps anyone in helping me brainstorm or not, but I will try and explain how this whole thing happened. I had this problem with it shifting in and out of OD last winter. In the spring I had to put on all new rear brakes. I had no more problem. Later in the fall I started having the problem again, I checked my rear brakes and sure enough, one side was completely gone while the other had 60% pad life left. I installed all new calipers/rotors/the whole shot once again last month. I still have a problem, but it's not as touchy as before I changed the brakes out. I found out last night that my rear passenger caliper has already froze up (being only a month old, it's pretty sad) so I put another one on again. I haven't had much of a chance to drive it on the freeway to see for sure yet. I don't know if this helps any of you vehicle guru's help me brainstorm. I fix computers, not cars. I can do cars, but it's not my thing. :?

[MotorCityMike]

Well, it makes sense to me that a drag on the car will make the ECM see a higher load, thus unlocking the TCC. I would check those rear calipers first, then try resetting the ECM.

 

If that doesn't work you may have to runa real time scan and watch what it is doing and if it is commanding TCC lockup/unlock.

[arvetus]

Well, I've had a chance to drive my car at a steady speed on the freeway. As Christmas approaches, I find myself driving 4 hour round trips to malls, etc. Anywhoo...it seems that the transmission does not want to lock until it is good and warm, so usually it doesn't lock until I've driven 5 or 10 miles. Then it will lock and unlock at random. Both rear calipers have been changed again in the past week after replacing them a month ago. I suppose it is possible to get 2 bad parts in a row, but it still seems unlikely. Rotors are also new with no rust to cause an excessive drag on the pads. At this point I'm not sure if it's the ECM or a solenoid. I think I'm going to try a solenoid first as it's the cheaper of the two. If that don't work, then I'll have to try an ECM I suppose. The plot sickens.

[1trucavalier]

It definitely does it on the 4T60. There are just so many TGP owners that had this problem. Its been said that the chip would fix it, its also been said that a new TCC switch would fix it. Who knows?? I got the switch but it haven't put it in yet.

[arvetus]

Ok, well everything on my 91 regal has been thourally tested (don't know if I spelled that right but oh well :? ) and everything tests ok. All electronics are working, the solenoid is working, and the transmission is mechanically sound even after 171,000 miles. Which leaves only one thing...one thing that I never even thought of or even considered for that matter. The thermostat. In talking to the mechanics at a dealer, I learned that the ECM will not let the transmission go into overdrive/lockup unless the engine reaches a temperature of at least 164 degrees. A simple road test with a scanner revealed that the engine temp never got anywhere near 164 degrees, thus explaining several things that have happened. 1.) it explains why I had a problem last winter, and it went away in the spring and now just came back in late fall. 2.) it explains why it takes so long for it to kick into lockup. 3.) it also explains my lack of heat, which I never considered to be an issue and thought I would have to replace the heater core, but it seams the heater core works fine . and 4.) it explains the crappy gas mileage.

 

I replaced the thermostat and Waalah! The problem dissapeared. And I am toasty warm in the process! So put this under your hat. Check the engine temperature before digging through the transmission to find a solenoid and ripping your dash apart trying to find the ECM

 

-steve

[1trucavalier]

good for you not good for me ! I replaced my thermostat, CTS, flushed coolant, griffin racing radiator, heater cored and burped the system about 10 times. My heat works fine, temp guage never exceeds half way, but the tranny still locks and locks when it feels like it. My solution is to BASH the GM designers for putting an auto in a performance car!!!!!