About a month ago my car stopped turning on. I went through all the normal checks: starter, battery, alternator and it was none of these things. Took the car to a mechanic and the problem that was established was a bad TCM that was in a lockout mode. So from there i took it to the dealer. The dealer has now told me that the ENTIRE tranny needs to be replaced because "the car thinks the tranny is stuck in first gear". Sounds like complete bs because it only thinks so Computer wise: i drove the car up to the first mechanic by rigging a thick gauge wire from the starter to the battery and the car had no problems shifting at all.

BUT: for a few weeks before the car stopped working the tranny was randomly changing gears. I would be driving and the car would suddenly downshift into 2nd or 3rd gear. Seems like the TCM is just going haywire.

Can anyone assure me the tranny doesn't need to be replaced? I can't believe that the tranny is done with 40,000 miles. All help is sincerely appreciated. Thank you in advance.

 

Anything?

 

What year is your car? Certain 04 and up models have the tcm integrated into the valve body...i'm sure there's all kinds of programming to the particular transmission that would make those not interchangeable

 

It's an 07 coupe. Why it wouldn't be interchangeable for another 07 valve body/tcm? It is integrated into the valve body.

 

What I don't understand is why was it possible for me to ghetto start my car (using the wire from starter to battery method) and drive it FREE of any problems for an hour upstate, yet the entire tranny needs to be replaced because the TCM is telling the car that it's in first gear? The car clearly isn't actually in first gear and it seems to me that the tranny is in perfect shape. And i would think any TCM/valvebody could be programmed to a car? I mean, that's how the original one was made to work right?