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Thread: 4L80E Shifting issues

  1. #1
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    4L80E Shifting issues

    Tune and Log are attached Thankyou
    Attached Files Attached Files

  2. #2
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    Log date is incorrect it was this morning after did the write entire.

  3. #3
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    it wont shift into 3rd or 4th

  4. #4
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    Do you have 28.5" tires or 24.5" Tires?
    Cause i see conflicting info on the Speed Calibration.
    Does it shift 1st into 2nd?

    All i see in the datalog is a P0342 code for cam position circuit A low and your trying to datalog wayy too many channels.
    The Driver side oxygen sensor doesnt seem too happy.
    Last edited by RDF1; 2 Weeks Ago at 05:10 PM.

  5. #5
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    Tires are 29.5" Its shifts 1st to 2nd as should. It never shifts out of 2nd i think. At full throttle it shifts 2nd to 3rd but wont go into 4th. Ill remove majority of the PIDs

  6. #6
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    You had wrong parameters in your Gear Ratio & Tire Size Calibration.

    Give this a try and see if anything changes.
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  7. #7
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    why would you disable torque management? i see the changes you made to the gear ratio & tire calibration just curious why that was done before i write your file.

  8. #8
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    Just what i do to see how the trans shifts then add it back in as needed.

  9. #9
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    Im about to see if it helps the issue. Also my gear selector does not feel right. from D-3-2-1 it feels like D-3-2 don't engage or something nor do they read accurate on my cluster. if i change gears manually 1-2 work but from 2-3-D do not. Just thought that should be put out there.

  10. #10
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    heres updated log
    Attached Files Attached Files

  11. #11
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    It really looks like you have a transmission issue. Its commanding the 1-2 2-3 and 3-4 shifts. But the input/output shaft readings aren't showing its happening.
    Is this a unknown transmission or a fresh build?
    It would be nice to see what the pressure manifold is reporting when the PCM is commanding the 2-3 and 3-4 shifts.

  12. #12
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    Progress

    At full throttle from 2nd to 3rd the truck acts as if it hits the rev limiter but it doesn't (rev) instead the RPMS drop an then it shifts.
    Attached Files Attached Files

  13. #13
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    Is there a PID I can log for the pressure manifold?

  14. #14
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    I dont think HPT has that available.

    I'd get a pressure gauge connected to the transmission or be prepared to remove transmission to have it rebuilt

  15. #15
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    That sucks Its brand new, was just rebuilt. what you did to the file made it shift. Im sure you can see that. Also it had a DTC solenoid B stuck on. does this change anything

  16. #16
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    I turned a couple DTCs off so i could get my truck inspected

  17. #17
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    I guess not

  18. #18
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    Solenoid B stuck on is prolly set because its trying to shift into 3rd gear but the PCM isnt seeing the shift happening.
    Id be getting with the builder and seeing what they can do.
    Who rebuilt it?