I have a '94 coupe LT1 automatic that is stock except for the aftermarket stereo system. Most of the time it runs flawlessly. The exception is it hot, humid weather and the coolant temp gets to about 210 with the oil temp at 212 or above. With these conditions and driving in OD or 3rd gear, when I attempt to accelerate (speed above 65 mph) there is a noticeable jerking in the transmission. I believe the TCC (Torque Converter Clutch) is probably causing this action, but what I don't understand is why does it only happen at these temps. If the coolant temp stays below 204 and oil temp 212 this never happens, that is, it accelerates with no jerking action. But when the coolant temp gets to about 210 and even if it cools off to 195 (while increasing speed) the jerking starts at about 70 mph. The TCC appears to be working fine otherwise since I can tap the brake and the rpm's increase.

I read a post that said that the main purpose of the TCC control is to turn the clutch action off - not to turn it on. With this in mind, isn't there a speed where the TCC control is turned on (around 70 mph)? Is this possibly what is going on....the speed turns the TCC on and then the controller turns it back off... or am I way off base? And why at these temps?


Thanks,
Ron

 

Are you sure it is the tranny and what kind of jerking.
Is it going in and out of gear or is the car speeding up and slowing down or something else?

Also, why would you be in 3rd gear over 60mph?
That puts some extra wear on the tranny as well as killing mpg.

 

Check your plug wires (or just replace them). I've had 4 GM cars with similar symptoms. The first one cost $100 for dealer diagnosis. Since then, replacing the plug wires has worked.
Sounds crazy but the high humidity and temp lead to arcing thru old insullation, especially under load (like when the OD is about to cut out and 'downshift').
To check the wires, disconnect the under hood lamps, find a dark place to park and fire up the engine. Look for sparks.
Good luck

 

That is very interesting information! I live in a hot, humid climate also, so I will store this away for future reference.

 

I like this idea! It could very well be a miss instead of the tranny. I will probably take the car out Sat...there is a local car show and cruise in...so I will check for sparks when I return. I'll keep you posted.

Thank you