Gst auto tranny issues

[TonyDeKilla]

I have a 1999 GST Spyder with an automatic transmission. When I got it, it was slipping in second gear so I did an R&R with a used tranny with 50,xxx on it. shifts better but still doesn't feel right. takes for ever to shift out of first and when it shifts into 2nd it shifts HARD. And when I'm driving regularly it shifts into 2nd at about 2500 after it is warmed up and shifts into 3rd RIGHT AFTER it hits 2nd? I found an Automatic transmission control unit on craigslist for a 97 GST. Would that control unit work for my 99 GST? and would it help at all with the shifting? The old transmission would do this too but would fluctuate between 2nd and 3rd without change of throttle becuase 2nd gear was not synchronizing. This tranny does not fluctuate but does have very odd shifting points.

Also... I have a 3" turbo-back straight pipe with 2 resonators. Would the lack of back-pressure affect the shifting? Sorry I'm new to turbos.

 

[SIMGSX]

There's so many and different things that could be wrong. My personal experience with my 97 GST was about the same as your describing. I went through 3 different trans and it seemed to by my luck that it was the transmission pump every time. Something was going wrong and it would eat itself.

You can check your solenoids and see if you are getting the right power to them. Because, your getting hard shifting and the solenoid pack might be faulty. So that might be the fix. I Also had to find a new TCU and I believe that they are all the same. If you got a 97 GST TCU i'm sure it will work in your car. And I don't think that back pressure in your exhaust would effect any shifting.

 

[tokyo98]

will the Transmission Solenoid cause the car not to go in gear when its cold?