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Thread: 4T45E Transmission Question

  1. #1
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    4T45E Transmission Question

    I have a 2008 Pontiac G6.. E38 computer. 3.5L VVT V6 Engine... All standard stuff.
    All stock.. I've done some adjustments on the shift points as the factory ones sucked horribly
    I bought this car new... I used the HPT just do trans adjustments.

    So, on the shifter (NO tapshift or anything else) It has the D and then the 3...
    Before I changed shift points the "3" would prevent it from shifting into 4th gear, but still had some other stuff with it diff than 'D'

    My question is this: I'd like to do some adjustments to the "3" position.. But in the trans tables I can't find anything about it.
    I've looked into the other options on the screen and none of them look as though they pertain to the "3" position settings.

    Thanks for any help
    Tom

  2. #2
    Tuning Addict 5FDP's Avatar
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    Without seeing the file it tough to say but if you ask me there is basically no difference. The 3 position is just there to stop overdrive.

    I've had grand prix's with the 4T65e and my current daily beater is a Malibu with the 4T40e (lower torque version of the 4T45e) and it has nothing there for the 3rd gear position. It's just stopping 4th gear/overdrive.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
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    As stock, the 3 position will shift pretty normal from 1-2
    but then 2-3 is delayed until 40 MPH no matter what TPS is.
    Then on the 3-2 downshift it only happens at about 37 mph even if zero TPS...
    I always thought it was a weird upshift/downshift pattern.. But it did keep me from 4th gear, so I used it sometimes around town.

    Now that I've got my 'normal' D pattern, I don't have to use it really, but I'd like to use it still sometimes when I just don't want 4th gear...
    But now the MPH numbers have magically moved up (prob along with my normal shift).. But I have looked at all the tables and can't find it...
    Maybe it's in a general setting, something I have to check enable/disable.. I'm just at a loss.
    I'll attach the tune file
    Attached Files Attached Files

  4. #4
    I have an 09 with a 3.9 and a 4t45 that im trying to lock in 2nd gear for circle track racing. Any help would be awesome

  5. #5
    Potential Tuner
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    Quote Originally Posted by [email protected] View Post
    I have an 09 with a 3.9 and a 4t45 that im trying to lock in 2nd gear for circle track racing. Any help would be awesome
    I'd imagine you'd have it to the 1-2 upshift really early (set rpm and tps parameters to make this happen), and a 2-1 downshift really late. Set 2-3 upshift for 9999rpm or something where it'll never do that... I imagine given some trial and error, you'll make it happen. I haven't tried tuning one, so you're on your own for settings.