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Thread: 4l60e shifting issue after swap

  1. #1
    Tuner in Training
    Join Date
    Sep 2015
    Posts
    31

    4l60e shifting issue after swap

    Hey Guys and Gals, I'm new to the forum....

    I've got a bit of a mess that came into my shop. I have HP tuners but am by no means expericanced with it, i mostly just write files and log with it.

    So here is what i have.

    71 gmc c-10 2WD

    08 LY5 / 4L60e swap (done at another shop)

    no codes, engine runs good, BUT. the trans shifts 1-2-3-4 imediately upon take off, it will shift maunally thru each gear, but will not downshift at all, does come back down to 1st when stopped.

    I'll attach the file i pulled from the ecm.

    im thoughts are that by the VIN # (from a 4x4) that there is either a 4X4 difference in the TCM tune or that the TCM is not getting written to? the TCM and ECM are not from the same doner to my knowledge.

    So, what i have come up with is to use a known 08 2WD Vin # and get GM dealer to flash tcm/ecm to a stock file and then disable my VATS and cats etc?

    any help would be greatly appreciated

    Thanks, Gerry Foster.

    P.S. please note i didnt not write this tune, i just uploaded it out of the truck....
    Attached Files Attached Files

  2. #2
    Tuner in Training
    Join Date
    Sep 2015
    Posts
    31
    ended up being a corrupt TCM.

  3. #3
    Advanced Tuner
    Join Date
    May 2010
    Location
    Behind the wheel
    Posts
    272
    Thanks for reporting back. I was curious what your fix was. I was going to ask if you had tried disabling the tap shift stuff.

    I had some strange transmission issues once and swapping TCM's then flashing my cal to the new TCM fixed it.