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  1. #1
    Join Date
    Jul 2005
    Location
    Marshall , MO
    Posts
    693

    Default 4l60e no 3rd or 4th gear

    Working on a truck for a guy he has ls with a 4l60e the harness and PCM is for a 4l80e. The PCM has been reprogrammed by street and performance. The tranny plug has been repinned and the correct pins and wires added. The problem is that the tranny will not shift under throttle if you let up it shifts fine. It will manually shift from 1-2. When it hits third the engine just revs. If you punch it it will down shift into second but as soon as you let off it shifts back to 3rd and is like it is in neutral. The big question is, is it the PCM or tranny? Also there are no CEL codes that call the tranny.



    Thanks
    Brad Shepard
    69 Malibu
    Marshall, MO


  2. #2
    Join Date
    May 2011
    Location
    Alaska
    Posts
    32

    Default

    Is this a new combo that has never worked correctly? Or has the truck been working properly for a long time, and now has this new problem?

    What kind of mods(engine/suspension/wheel&tire package) is this 4L60E being punished by? The 3-4 clutches are always weak when the power to weight ratios get out of hand.
    Roger

    1967 Camaro, work in progress.
    2001 Silverado, 11.8 at 112, MagnaCharged LM7.

  3. #3
    Join Date
    Jul 2005
    Location
    Marshall , MO
    Posts
    693

    Default

    This is a new combo and has never worked properly. The truck is a early 90's 4x4 short bed this combo has never been punished (it has never worked right) it might have a lift if it does it isn't much the wheels are 16's or 17's and probably a 28-31 inch tire somewhere in there. As far as I know the engine is a stock LS1 from a 98 camaro the PCM and wiring harness are from a truck or something that originally had a 4l80. He got a "Good Deal" on the 4l60 so he put that in it. I moved one pin at the tranny plug and added the two pins and wires at the plug and the PCM. The tranny sat around for a couple of years after it was rebuilt so not completely sure where to start.
    Brad Shepard
    69 Malibu
    Marshall, MO

  4. #4
    Join Date
    May 2011
    Location
    Alaska
    Posts
    32

    Default

    I believe it's a mechanical issue in the transmission. Pull the pan & see what's in there.
    Roger

    1967 Camaro, work in progress.
    2001 Silverado, 11.8 at 112, MagnaCharged LM7.

  5. #5
    Join Date
    Jul 2005
    Location
    Marshall , MO
    Posts
    693

    Default

    That was the conclusion I cam too as well. Not what the owner wanted to hear as it was supposed to be a reman unit he purchased it from a "friend" working at a dealership. two years ago and is just now getting around to putting it in something.
    Brad Shepard
    69 Malibu
    Marshall, MO



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