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Thread: Help: Problems running a 2004 transmission in a 2000 Grand Am

  1. #1
    Tuner in Training
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    Oct 2006
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    Help: Problems running a 2004 transmission in a 2000 Grand Am

    I need some help in trying to figure out what is going on with my 2000 Grand Am GT. I replaced the transmission with a low mileage transmission from a 2004, however at the time I did not realize that they made changes to the pressure switch manifold (2004 has a few less switches) and therefore the 2000 VCM will not allow the car to shift into 4th gear and throws a P1810 code. I have disabled the P1810 reporting in the VCM, however it is still not wanting to shift into 4th gear.


    With the 2000 VCM the car runs and drives great aside from the transmission not going into 4 gear.

    I read that the hardware changed in the 2004 VCM's, so I purchased a VCM from a 2004 and installed it in the car. The only issue that I am having with the 2004 VCM is that the car will not restart once the engine is hot, it just cranks. It will however fire up immediately when the engine is cold and run/shift great until shut off. With the 2000 VCM I do not have the hot restart issue.

    At this point, I am looking for any help I can get as the transmission is already in the car and I don't want to mess with pulling it out again. I have attached a few wiring diagrams and I am stumped where to go at this point.

    Update: Using the 2000 VCM, I unplugged pin 22 (Circuit 1224) and taped it off. I then added a ground pin and hooked it to a momentary push button switch, which the car will now shift into 4th gear I hold the button on the switch so it is a constant ground. When I release the button, it immediately drops back to 3rd. At this point I am not sure if I should just wire pin 22 to a constant ground or if that will cause other issues. Any advice would be appreciated.
    Last edited by GMV6Power; 09-15-2013 at 11:00 PM.

  2. #2
    Tuner in Training
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    2000 Wiring Diagrams:










  3. #3
    Tuner in Training
    Join Date
    Oct 2006
    Posts
    22
    2004 Wiring Diagrams:









    Last edited by GMV6Power; 09-15-2013 at 10:59 PM.