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Thread: 4L60e - is it busted or is it my tune?

  1. #1
    Potential Tuner
    Join Date
    Dec 2020
    Posts
    2

    4L60e - is it busted or is it my tune?

    Hello all

    After many internet searches I prostrate myself before the HP Tuner gods. For some background, this is my first time using HPTuners but I've been playing with cars for 30 years now.

    My vehicle is a 1998 Tahoe 4x4 that I recently swapped a 5.3 into due to a valve issue. I kept the 98 4L60e because it was showing no signs of having any issues. I'm running an LM7 with an aftermarket harness mated to the 98 harness, following the directions on lt1swap.com almost to the letter. It runs great and feels strong, except...

    Gears 3-4 feel like they are pretty much gone. Putting around 1-2 feel ok, and I can accelerate decently, but once it shifts to 3rd it's almost like going into neutral. I used the BlueCat tool to sett all the parameters I could. The internet says the 3-4 clutches going out in these is pretty common, but I was hoping someone with more knowledge could look at this log and my tune for anything crazy.

    On the log, 2:58 to 3:08 show whats going on pretty well. From a stop it accelerates fine, until it commands 3rd. Then the RPMS bounce off redline but the speed starts going down, and the tranny freaks out vacillating between 3-4 but no acceleration. This is at only 50% TPS, I'm not even giving it the beans. It does this at lower speeds without the 4-th gear try too, see 3:34 to 3:44. I can blip the throttle like it's in neutral when it thinks it's in 3rd.

    To top it off, when I stop I think I smell clutches. I know what a burnt manual clutch smells like and this isn't the same, but it's not exhaust or burning rubber either.

    Thoughts?

    Much appreciated.

    -Beau
    Attached Files Attached Files

  2. #2
    Potential Tuner
    Join Date
    Aug 2019
    Posts
    5
    need a transmission rebuilt