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Transmission problem ?


jmy's Avatar
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12-22-02, 03:10 PM   #1  
jmy
Transmission problem ?

I have a 1992 Pontiac Grand Am automatic transmision (th-125/C -3T40) 2.3L engine that has a problem when stopping, it will stall when up to operating temps. It will not occure untill the car has been driven for a period of time. When this problem occurs the car will restart with no problem and idle fine. When pulled into gear it will stall, let the car set for a half hour it will work fine untill it warms and you try to stop. When the problem occures, the car will act as though it has a clutch that was not disengaged, it has a slight bucking before it stalls. If I can and feel this happening and don't bring the car to a complete stop the motor takes off OK and the transmission shifts find. I have tested the motor with a Actron Scan Tool for rich/lean conditions and that is not the case, I do not see a problem with the engine, or any of its sensors. The car has a lock-up converter, what could keep the converter from disengaging? Could the vehicle speed sensor be giving a false signal to the ECM allowing the computer to keep the TCC Sol. on? I get a reading on the Scan tool that the 3rd gear switch is ON when in park and idling, is this normal? It is the only gear switch indicated. I know some transmissions use the 3rd or 4th gear switch to engage the torque converter clutch. I have know of problems with it not engaging but have not experianced one that failed to disengage. Any ideas on resolving this will be greatly appreciated.

 
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12-22-02, 03:33 PM   #2  
Joe_F
The problem is a bad TCC solenoid, it is staying engaged. Very common on the 125C, happened on my own Cavalier.

You can usually disconnect it and leave it that way, it will only sap a little fuel mileage. GM had a problem with internal leakage on some 125C models. The side cover has to come off to fix it, etc, and it's usually not worth it.

On my 89 Cav, the check engine light doesn't come on, not sure on that newer GA if it will. Disconnect the TCC plug (square plug) on the top of the tranny and see what happens.

 
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01-02-03, 04:21 AM   #3  
jmy
Transmission problem

Joe F.
Your response to my problem seems to be working. I unplugged the TCC and the car so far has not duplicated the problem. Thank You for sharing you experiance it saved me a lot of time.
Joe Y.

 
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01-02-03, 07:12 AM   #4  
Joe_F
Good show and you're welcome.

 
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