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Thread: 2-3 shift problem 4L80e

  1. #1
    Potential Tuner
    Join Date
    Jun 2018

    2-3 shift problem 4L80e

    Hi .

    I hope someone can help me. no idea what i am doing wrong.
    Have a 12205612 operating system.
    The computer did not belong to this engine. Have an LS1 5.7
    And 4L80e gearbox in a 1939 GMC truck

    Engine works fine. I only have 1 and 2 gear and nothing else.
    When I switch on the solenoid 1-2 with vcm scanner I hear it click.
    When I turn the 2-3 on I don't hear anything.

    I measure the yellow / black wire at point 47 (red) 12v.
    When I connect it to ground I hear a click in the gearbox
    So solenoid works.

    I look in vcm scanner at the channels:
    Shift solenoid 1-2. i can switch it on / off with vcm scanner
    Shift solenoid 2-3. remains off whatever I do.

    If I turn on 1-2 solenoid and then turn on 2-3. Then 1-2 off. Then 1-2 solenoid remains on until I turn 2-3 off

    Have used the transswap file 2000 silverado 6.0 4L80E 612 OS.hpt.

    hope someone can help me
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    Last edited by mts-rides; 3 Weeks Ago at 06:02 AM. Reason: more info

  2. #2
    Potential Tuner
    Join Date
    Jun 2018

    Is it possible.
    That the input from the computer is not working?

    Can I test that?
    Otherwise I will have to buy a new PCM and also a new credit.
    Maybe only to find out that it is something else.

    Don't know if it's a software or hardware problem.