i dont even know what the tcc is? i dont have the car..its at the dealer. im waiting on a call back from the warranty company. i may have to have the car taken to another shop. the dealer is 115 an hour for labor and they only cover 75-80 an hour.

TC is torque converter, TCC is TC clutch. When you drive stop and go, the TC is a fluid coupling, meaning the engine drives the transmission by spinning two fans (turbine & pump) inside a pool of transmission fluid. At very low RPMs, the fluid allows the two fans to "slip", but as you increase RPM, force from the turbine transfers to the trans fluid, and then to the pump, which causes the output shafts to turn the wheels.

In short, the engine doesn't drive the transmission. The engine drives fluid in the TC, which then drives the transmission. This is why you can stop the car and stay in gear - because the fluid allows some slip. With a manual transmission, there is no fluid or slip, so you stall.

This is how it looks inside:



The two fans don't actually touch each other, they spin in the trans fluid. The fluid has special properties that allow it to transfer power from the engine to your transmission, and out to the wheels. Whenever you idle, drive stop-and-go, under about 50 mph, or accelerate hard, the TC is in fluid coupling mode. Whenever you do this kind of driving, the trans fluid heats up, and so does the TC and the rest of the transmission.

Once you get up to cruising speed, above 50 mph or so, a solenoid trips the TCC and engages TC lock-up. This is an electromagnet that makes a mechanical coupling from the engine to the output shafts. In a sense, the two fans lock together, so the fluid is no longer used to transfer power. Instead, there is now a hard connection that lets the fluid take a break and cool off.

As long as you stay above a certain speed, and don't accelerate too hard, the transmission will remain in TC lock-up mode to keep fuel economy and let the transmission operate at a safe temperature.

IF the TCC fails to lock up, the transmission works in fluid coupling mode all the time, killing fuel economy and causing trans temps to rise. You can get away with it for trips under 50 miles, but for very long hauls, you can cook your trans without TCC.

It sounds like this is what happened, but the PCM is supposed to turn in the SES light when TCC fails, to let you know. Did the service engine light ever come on?

very informative..no lights came on...

Ok..so i talked to the guy who diagnosed my car yesterday..
first off...the idiots actually took it on the road after i told them it was undriveable. lol hence why it wqas towed to a dealership and towed to another one lol
but anyway..the guy said what was happening was the tranny fluid was heatin up causing to shut it down and damage a couple of internal parts. repair is underway and should be done before this weekend.

any idea why the tranny fluid was getting so hot?

just the age of the car he said. sumthin mustve just set it off on that friday morning and it went downhill from there.

"The age of the car" = I am totally unqualified for my job.

The age of the car? Your transmission fluid only had ~60k miles, right? The fluid should last 2-3 times that long, and it doesn't just spontaneously fail like that. I agree with Jack, this guy can do better than that. Something caused that fluid to cook.

well..i got my car back....very smooth shifting now..then only thing im very disapointed with is the cars alignment is off by a lot now. im waiting to here back on how the hell this can happen.....and for some reason...the car seems a little slower.

Alignment can be off because of how the cradle supporting the trans / engine is bolted in. A GM tech friend of mine used to have to move the cradle around on certain cars when they couldn't get the alignment correct by normal front end adjustment.
So, the same thing can happen when the cradle has been removed and reinstalled for trans overhaul.
Need to have trans shop pay for proper alignment and make alignment tech aware that the cradle needs repositioning.

i already called and left a message for the guy to hopefully correct this.

"I screwed up your alignment and didn't catch it" = I am totally unqualified for my job.

lol thats the dif between a service advisor and a mechanic.

Or a Mechanic and a Technician.
Huge difference.