Thread: First Gear downshift issue

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  1. #1 First Gear downshift issue 
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    Hey folks.

    I have something going on with my 08 GXP. I noticed that the tranny works fine 95 percent of the time but when I come to a stop it will sometimes not shift into first gear and then it will get a hard shift to first as soon as I give it some gas. This doesnt happen every time it actually depends on how much gas I give it. When in tap shift it will down shift to 1st without problem even when I let it auto downshift to first. In fact the tranny acts perfect when in tap shift. I took it to the dealer and they simply said it was normal but I find that hard to believe.

    To me there is a delay when its in auto mode like its hanging in 2nd gear till I get up and go and then it quickly shifts to first. Is this a common issue? Is the tranny going out on it?

    I appriciate the feedback
    08 GXP all stock
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  2. #2 Re: First Gear downshift issue 
    I live here. 02NavyBlue's Avatar
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    How many miles? If it doesn't go anywhere until you give it more gas in drive, that's not normal. It seems to be somewhat common on the 4t65e.
    2006 Grand Prix GT S/C 109k - Modded Transgo Shift Kit, Gutted Airbox, Dash Cam, and Inlays. Retros soon to come.
    2002 Grand Prix GT N/A 127k - Same as 06 Plus: Trans Cooler, DIY Aux Input, LED lighting, Suspension Upgrades, Tint, Retrofits.
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  3. #3 Re: First Gear downshift issue 
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    Hi there.

    121K on the tranny. I know for sure its stuck in 2nd gear because if I give it some gas sometimes it will go but obviously not go very fast. Having it in Tap Shift makes the problem go away. As I said it only happens once in a while. Only happens from a stop so if im going 25 and I step on it the shift to first is normal.
    08 GXP all stock
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  4. #4 Re: First Gear downshift issue 
    I live here. 02NavyBlue's Avatar
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    Oh so you're sure it's in second gear from a stop. I haven't heard of that happening before, how about we get a trans guy over here
    2006 Grand Prix GT S/C 109k - Modded Transgo Shift Kit, Gutted Airbox, Dash Cam, and Inlays. Retros soon to come.
    2002 Grand Prix GT N/A 127k - Same as 06 Plus: Trans Cooler, DIY Aux Input, LED lighting, Suspension Upgrades, Tint, Retrofits.
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  5. #5 Re: First Gear downshift issue 
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    I have put it in tap shift mode when the problem is actually happening and the head up display is indicating "2" for a moment and then it quickly shifts to "1". I have never seen it stuck in any other gear. To me it sounds like the TCM is messing up somehow and simply not downshifting to 1st at a stop. Everything else works fine. If the tranny was wearing then I would expect to see the problem under all other driving conditions like accelerating or manual shifting, etc... But I could be wrong. I expected the dealer to at least give me some idea but they did not. I am considering taking it to another dealer and seeing what they think.
    08 GXP all stock
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  6. #6 Re: First Gear downshift issue 
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    Mine does this too, I haven't figured out why. I actually haven't tried to figure out why I just live with it. About once a every couple weeks you go to take off from a stop sign or something, set your foot on the throttle and it takes off in second and lugs and if you lean on it a little more it kicks into first and goes. On mine (non tapshift) as soon as it does it if I pull the shifter into manual first and it drops into first. I have an extra clutches in every drum with no waved plates plus a aftermarket boost valve, afl valve and transgo shift kit with customized calibration so I had just attributed it to that.
    1999 GTP Coupe ------ Comp Cam 76-802-9, 2.7" pulley, S2IC, N*, FWI, SD Headers, DHP Tune, Built trans (single 3.29s, 300m), Magnaflow Catback, 60#injectors, E85, MT ET Street DR's, Fbody brakes, PRJ pump/rails. 302whp/328ft-lbs.......12.41@110mph
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  7. #7 Re: First Gear downshift issue 
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    Quote Originally Posted by Anthony Smith View Post
    Mine does this too, I haven't figured out why. I actually haven't tried to figure out why I just live with it. About once a every couple weeks you go to take off from a stop sign or something, set your foot on the throttle and it takes off in second and lugs and if you lean on it a little more it kicks into first and goes. On mine (non tapshift) as soon as it does it if I pull the shifter into manual first and it drops into first. I have an extra clutches in every drum with no waved plates plus a aftermarket boost valve, afl valve and transgo shift kit with customized calibration so I had just attributed it to that.
    Sounds like a TCM issue really. If you force it to 1st then all is well. I dont think there is anything internally wrong with my tranny. I think its more computer related.
    08 GXP all stock
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