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Thread: 6L80 - TCC pressure & slip not what I expected

  1. #1
    Tuner in Training
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    6L80 - TCC pressure & slip not what I expected

    2018 Silverado 5.3L 6L80. Transmission is rebuilt, and new Precision of New Hampton HD (billet) converter. Pretty much a newbie with HP Tuners. Used HP Tuners to disable TCC in gears 1-3, set 0 slip in 4 through 6, set TCC Regulator Offset to 90psi and gain to 1.0. Figured then I would see a really firm lockup but instead I see TCC pressure as low as 20psi and some TCC slip while cruising in 6th gear. In the image below there is a long section at 65mph on cruise control. I expected to see higher TCC pressure and no slip, yes? Seems wrong to me. Suggestions? On the road, the TCC lockup feels firm.

    And a minor issue in the Scannner - the current gear does not show on the scan, but the instantaneous value is correct, see top left in Channel, value is 6. Is the chart problem because the 'gear' is not just a number (scalar), it can also be Park or Reverse?

    Thanks.

    vcm-scanner.jpg
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    Last edited by DickForster; 03-18-2024 at 11:43 AM.

  2. #2
    Advanced Tuner
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    Quote Originally Posted by DickForster View Post
    2018 Silverado 5.3L 6L80. Transmission is rebuilt, and new Precision of New Hampton HD (billet) converter. Pretty much a newbie with HP Tuners. Used HP Tuners to disable TCC in gears 1-3, set 0 slip in 4 through 6, set TCC Regulator Offset to 90psi and gain to 1.0. Figured then I would see a really firm lockup but instead I see TCC pressure as low as 20psi and some TCC slip while cruising in 6th gear. In the image below there is a long section at 65mph on cruise control. I expected to see higher TCC pressure and no slip, yes? Seems wrong to me. Suggestions? On the road, the TCC lockup feels firm.

    And a minor issue in the Scannner - the current gear does not show on the scan, but the instantaneous value is correct, see top left in Channel, value is 6. Is the chart problem because the 'gear' is not just a number (scalar), it can also be Park or Reverse?

    Thanks.

    vcm-scanner.jpg
    I doubt anyone will be able to help without you first sharing your tune and a log but I can tell you why you don't see the current gear in your graph. That's because at one point you went to reverse or neutral so that PID has letters in there instead of only numbers at one point.It is a really annoying shortcoming of HP Tuners, hopefully they will fix it down the road. You can export the file to excel and replace those letters with numbers to get the graph to work once you re-import it, but it is a pain to do. Best thing is to make sure you don't start logging until you are in OD range and stop logging before you get it out of OD range.
    Robert Moreau
    Technical Sales and Marketing Support Specialist
    TransGo
    2621 Merced Avenue El Monte, CA 91733 USA
    Calibration | Innovation |Performance
    https://transgo.com/our-products/

  3. #3
    Tuner in Training
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    Quote Originally Posted by TransGo Robert View Post
    ... I can tell you why you don't see the current gear in your graph ...
    That's what I thought, and will avoid that issue next time. Original post upated with tune and log file.

    Thanks.

  4. #4
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    Quote Originally Posted by DickForster View Post
    That's what I thought, and will avoid that issue next time. Original post upated with tune and log file.

    Thanks.
    Thanks for adding the files. It is definitely a command issue, unfortunately I don't know enough about Tuning to be able to tell what is not set right in your tune. Seems to me you have it set for zero slip everywhere but obviously at one point it wants it to slip for some reason. Hopefully someone else can chime in and tell you what needs to be tweaked.
    Robert Moreau
    Technical Sales and Marketing Support Specialist
    TransGo
    2621 Merced Avenue El Monte, CA 91733 USA
    Calibration | Innovation |Performance
    https://transgo.com/our-products/