Transmission Problems?

A few weeks back, I was driving through town when I came to a traffic light. I stopped as usual, and when I took off again, it almost felt as if I was rear ended. Alarmed, I immediately looked in my rear view mirror, only to find that I was the only car on the road. I continued driving and got to my destination. When I left, I put the car into reverse, and when I put it into drive, it jerked forward. I continued driving and every time the car shifts, it shifts extremely hard and jerks forward. This has been ongoing for a couple weeks. The check engine light came on as well, but with work schedules and such, I haven't had the opportunity to take to dealership. Any suggestions to what it could be?

i couldnt tell ya what it is, but intermittently i experience the same exact thing in my '08 GT. It shifts amazingly hard sometimes, and other times it will slip really bad.

i have brought it to the dealer a number of times, and they cannot get it to act up. The guy told me that on cold starts it is "normal" i told the guy that i am not a dumba$$ and know this type of hard shift is NOT normal.

bring it to the dealer and have them scan it for codes. They couldnt find any stored in mine...maybe you'll have better luck. Let me know what you get.

I'm going to take a guess that you have an automatic. The g6 transmission like stated above can shift a little hard at times. The main cause for most people is the computer in the car. A reflash of the PCM can sometimes remedy the rough shifts. Some also have had upgraded (tuned) their PCM and TCM's and noticed the shift become much more smooth and precise. However in your case since you have a Check engine light i would have to take a guess something else maybe wrong causing the rought shifts such as a short within a sensor. I would take it in and get the codes scanned and see if their is something else causing that issue.

There is a TSB on this issue, harsh shift- MIL on. Once the codes are pulled they can see if yours has this problem.

Seems the wiring harness inside the transmission was poorly routed causing the torque converter clutch solenoid wire to eventually cut thru and ground causing high internal line pressure (Bang! shift). The update is a revised harness.

You should get it serviced soon as it's not good on the mechanical.

A little fresh look at it, my tranny is doing the exact same problem (literally the same) and I am 99.9% sure its my vacuum line. Found a little connection that is fairly loose, letting out air and causing problems. Soon as I get the leak behaved the tranny starts shifting a little better and my idle is more calm.

Still havent gotten a fix but... it could be the o2 sensor as well. BE carefull of the dealer.. last time i took it to them to look at the o2 and they tried to convince me the transmission was blown lol.

Loved their faces when they fixed the o2 wireing harnesss and the transmission stopped shifting hard.

http://www.automotiveforums.com/vbulletin/showthread.php?t=1023728

Thats the link to my post f you want to see the pics of the vac line connection.

Good luck!

I have also just recently had the same problem with hard shifting and check engine codes of P0013 and P0014, pointing to exhaust problems. Then yesterday my battery shorted and had to be replaced. I don't know if the bad battery is any way related to the trans problems, but I do know that all this crap is interconnected and any electrical problem could affect trans and engine performances in weird ways. I replaced the battery and cleared the faults and my car ran smoothly to work this morning without problems but I'll remain cautiously optimistic for a while.