Thread: Best Replacement Tranny (Aftermarket possibly?)

I have an 03 Grand Prix SE with the 3.1L and 4T65E M15 transmission.

I had the typical TCC solenoid problem (replaced it and still other issues), and have been thinking of trading the car off once the issues are resolved. However, I don't see another car I like as much as my Grand Prix. If I could get a transmission (maybe an aftermarket) that will not have this same issue in 50k miles, I'd keep this car, and invest in the transmission. I drive alot, and on WV roads which are basically wide open straights mixed with 15 mph turns. Alot of shifting going on.

Any suggestions for a replacement tranny? I wouldn't want to spend more than $2500 if possible since the car's not worth much more than that.

Is it shifting off? No sense in replacing the trans if it's still working. What issues are you having?

I removed the sidepan (while transmission was still in the car), replaced both solenoids and the switch on the accessible side of the tranny. It fixed my hard shifting problem, but for some reason, even after resetting the TAPs and the PCM, my SES light goes off, but comes right back on not long after starting. Still throwing the "TCC stuck on" code. No hard shifting still, though, so I'm confused what's causing it. I have also noticed the car won't downshift like it should when taking off hard. That may be caused by an out of adjustment TV cable, but I'm wondering if it's related to my "TCC stuck on."

I'm wondering if my TCC is just toast and the solenoid wasn't the problem after all. But wouldn't that cause hard shifting (which I don't have since replacing the solenoid?)

There are 3 general causes for code P0742 "TCC Stuck ON" and they are briefly described on my website on the info page. I have a 10 or so page explenation or diag chart on how to check into this problem in depth to isolate what the problem cause is. If you are interested send me an email and I can send it to you to look at. Most of it is electrical diag work to isolate the problem. I often see this code when the TCC solenoid is plugged up with debris that came from the torque converter and replacing the solenoid helps for a while but the problem often comes back. Since you just replaced your solenoid and the code persists I would suspect you may have an electrical problem but it will take a little troubleshooting to determine. As the others said you should make sure what you have going on first instead of spend the money on a trans only to find out the problem will still be present because it wasnt really in the trans.

I had the car to a tranny shop first for a diagnosis, and they eliminated it being an electrical problem.