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Thread: Sloppy Shifting H2

  1. #1
    EFILive Distributor dfe1's Avatar
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    Default Sloppy Shifting H2

    Has anybody done any tuning on a Hummer H2? I just started working on one and when I took it out for an initial test drive, I noticed that the shifting is extremely sloppy. It's almost as if each gear change is made in two stages and it literally takes 1-1/2 to 2 seconds for an upshift to take place. The shift takes noticeably more time to complete than in the Silverados/Sierras I've worked on. I'm just wondering if this is a normal H2 shift cal or if this particular vehicle has a trans problem.

  2. #2
    Lifetime Member 87gmc's Avatar
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    sounds like my Z71 :?

  3. #3
    EFILive Distributor dfe1's Avatar
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    I've been doing some research and some of the shift problems may be (at least to some degree) a result of the adaptive transmission data. I'll post more if I find a "cure".

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    EFILive Reseller wait4me's Avatar
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    if you send me that h2 file ill give you something to try jes
    "If you can leave a black mark on the pavement, from the exit of one corner to the braking point of the next one, you have enough horsepower."

  5. #5
    Lifetime Member 87gmc's Avatar
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    hey wait4me your leaving me out


    Can you answer me though waht do you think is effecting the shifts.

  6. #6
    EFILive Distributor dfe1's Avatar
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    I have a few more things to try, but I'm beginning to think that it's going to take a mechanical adjustment to bring the shifting around. The shift table in a 2002 Silverado I did is very similar to the one I did for the H2, yet the shift quality is completely different. I'm going to try the change that wait4me recommends, then reset the transmission adaptive data and see if that makes any significat change. I'll post what I find.

  7. #7
    EFILive Reseller wait4me's Avatar
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    send the files to jessebubb@yahoo.com ill check them out. jes
    "If you can leave a black mark on the pavement, from the exit of one corner to the braking point of the next one, you have enough horsepower."

  8. #8
    Lifetime Member GMPX's Avatar
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    Change the desired shift times to '0'. Then there should be no adaptive learning.
    Have you read the adapt values in the scantool?.

    Cheers,
    Ross

  9. #9
    EFILive Distributor dfe1's Avatar
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    Haven't had a chance to work with the vehicle again-- the owner has been out of town. By the way wait4me, have you had a chance to look over the file I sent?

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