97 grand prix trans prob.

Drfloppy · 04-05-2008, 07:05 PM

Hello everyone, I have a 97 grand prix 3.8 with 226,000 miles on it.. Motor and trans have never been rebuilt but, I do take care of oil changes and fluid filter changes. The problem I am having now, and Im sure you are all going to tell me it is time for a new trans, but what it is doing is, it shifts fine from start up. but if you go to pass someone, it will not downshift. If I pull the shift lever back, it shifts very smoothly. and then will shift back up into drive when it needs to. And if I come to a stop sign, and go to take off, it does go back to first gear. Just for some reason it wont shift at all no matter how doggy it gets, or how much I floor it, it will not shift on its own.. Any help would be great.. Thanks a lot guys.. I know you are going to tell me its new tranny time.. Thank you in advance.
Dale

tblake · 04-05-2008, 07:39 PM

Check that throttle Boost cable that runs from the trottle body to the trans, sometimes they break and the tranny wont downshift, and sometimes they just need adjustments.

Also take a look at the vacuum line that goes to the vacuum modulator on the tranny. The modulator is located towards the driverside of the tranny. Pull the vacuum line off and make sure its not filled with tranny fluid. If it is all you need is a modulator, which is quite easy to replace.

Drfloppy · 04-16-2008, 01:01 PM

Hey, Just wanted to let you know that the problem with my car was the Throttle Position Sensor. We changed that and now my car down shifts nice and smooth.. Good for another 225,000 miles !! I hope.

tblake · 04-16-2008, 06:21 PM

Nice! Thanks for letting us know. We love feedback!!!

I hope I can get that many miles out of my original motor and tranny. So far so good!

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