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Thread: 6r80 3 to 4 shift problem

  1. #1
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    6r80 3 to 4 shift problem

    I have a 2015 Mustang Gt Auto. I am currently tuned by Wengerd Performance.

    My problem is that when I am wot and shift from 3rd to 4th the car shifts into 4th, waits half a second, then shifts into 5th. It will then shift into 4th again after a few seconds or so. It only happens when I shift above 7k rpm (redline set to 7,800). I am in sport mode using paddle shifters so the car should not be shifting (unless when rpm gets too low).

    The 1-2 shift and 2-3 shift is fine. Haven?t done wot 4-5 or 5-6 above 7k rpm.

    Ive been going back and forth with my tuner and they can?t figure out the issue, so I thought I would post on here. Any help I could pass along to the tuner would be much appreciated!

    I will attach logs when I get home.
    Last edited by tdstuart; 11-21-2021 at 04:46 PM. Reason: Fix spelling mistake

  2. #2
    Advanced Tuner small tuner's Avatar
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    dose this problem happen when trans on Drive mod ?
    Turbocharged COYOTE

    PM for E tune / Remote Tuning session

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    No it doesn't, only when using paddle shifters. And I'll attach logs in a few forgot to post them.
    Last edited by tdstuart; 11-23-2021 at 12:56 PM.

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    Senior Tuner veeefour's Avatar
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    Quote Originally Posted by tdstuart View Post
    No it doesn?t, only when using paddle shifters. And I?ll attach logs in a few forgot to post them.
    Tell Darylle to adjust SST tables.

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    Quote Originally Posted by veeefour View Post
    Tell Darylle to adjust SST tables.
    What do the SST tables do? And what specifically should I tell him the adjust?

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    Another log this time with more transmission information.

    Revision F2 Test.hpl

  8. #8
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    SST is select shift transmission mode. it means you pressed the paddles or +/- buttons. With lever in drive you have a time out for this mode, with lever in sport there's no time out for SST mode.
    In this mode it ignores the shift scheduling maps and goes off user input.

    You are right, when you are using the paddles it should not be shifting with out user input, unless speed is to low.

    There's a table that defines that upshift and raises it out of being used.
    There's also a table for preventing down shift if speed is too high.
    These are those thee tables stock, all under the shift scheduling tab and anyone can find.

    Select shift.jpg

    If you paddle it into 4th at a lower speed, and run up through the RPMs, does it shift or hit the rev limiter?
    If it doesn't shift and hits a rev limiter, I would say it could be the downshift prevention logic kicking in with the user input on an "upshift" paddle.
    If it shifts, there's something about your car thats undefined in HPT or wrong with your car and its in a FMEM mode. Failure Mode Effect Management. You would normally get a code or something that indicates this.
    I've heard of logic defining a tap vs a hold of the paddle. Then what to do if the paddle is held. Not common on upshifts.

    Do you have a relay transbrake wired into the clutch control, or a digital one? Those can cause all kinds of issues.
    Then also since all these tables are based on speed, speedo calibration matters. Different rear gear and tires can have an effect. This usually isn't a problem as the upshift speed is 300mph.
    The paddles were how the 2020 GT500's were getting around the shift maps and shifting higher. What you describe is strange.
    Last edited by murfie; 11-26-2021 at 04:30 AM.
    "We can never be right, we can only be sure that we are wrong"- feynman

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    Do you mean shift into 3rd and see it hits the rpm limiter or shift into 4th and hit the rpm limiter.

    Honestly kind of scared to do either as the car has 100k miles, stock oil pump gears, and rpm limiter is set to 7,800.

    My tuner said they have tried everything and are working with hptuners to find a solution.

  10. #10
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    4th

    You don't have to hit the limiter just see if you can get up to 7600 and let off or if it shifts at a lower RPM.
    "We can never be right, we can only be sure that we are wrong"- feynman

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    Okay, so I revved 4th to around 7,500. It didn't shift but when I did try to upshift to 5th it wouldn't let me. Once I let off the throttle I was able to shift to 5th.
    Last edited by tdstuart; 11-27-2021 at 12:59 PM.

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    Please help anyone!

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    Quote Originally Posted by tdstuart View Post
    Please help anyone!
    Did you try cross referencing another 6R80 tune? I posted my tranny tune, which was given to me by a well known tuner, that you can cross reference.