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Thread: 600 rpm slip limit

  1. #1
    Lifetime Member killerbee's Avatar
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    Default 600 rpm slip limit-TCC lockup

    With a bit of trial and error logging, it seems that lockup will not proceed when outside the slip limit of 600 rpm noted in D5072. I suspect this is what has inspired many of the "WOT lockup problem" threads through the years from the performance oriented crowd. At high throttle settings, slip rpm is greater than 600 rpm with stock converters until a very high engine rpm. Oddly, I only recently noticed this, since I don't spend my life killing parts at the track.

    For the reverse engineering gurus: is there a way to build a tune/OS with an expanded D5072, say to 1200 rpm?
    If not, how can we get inside the 600 rpm lockup?

    Thanks.
    Last edited by killerbee; January 10th, 2012 at 11:27 AM.
    Michael, Systems Engineer 04.5 D-max LLY, Phoenix, Arizona Email
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  2. #2
    Lifetime Member dansdieselp's Avatar
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    X2?
    Dan's Diesel Performance
    www.dansdieselperformance.com

  3. #3
    Lifetime Member THEFERMANATOR's Avatar
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    I know this has been asked several times, and the only current offerring is a lock-up controller. I wish we could get more of teh lock-up controls though as it is really annoying for me anyways running along at 55 in lock-up and everytime I let off the throttle it unlocks the converer even though I have teh unlock point set WAY low. With 3.42 gears the unlock point set in the TCM is just a bit to high for me.
    1995 GMC 2500 SUBURBAN powered by 01 DURAMAX/ALLISON, little of this, a little of that,
    DIAMONDEYE 4" exhaust, CORSA muffler, AFE stage 1 dry filter, custom tuning by me, KENNEDY single pump and pump rub kit.

  4. #4
    Lifetime Member killerbee's Avatar
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    I just researched some old threads. If it was the companies decision not to pursue this, I apologize, but I have not seen where that position was made. It seems plausible that it could be an easy (and profitable) improvement, and honestly, this is a biggie. It would be an application for racing and street refinement alike. Anything that eliminates unnecessary dash clutter is definately big in my book. It is very clear in the logs, 599 slip = lockup. Just thought this emphasis might narrow down the places to look for it.
    Michael, Systems Engineer 04.5 D-max LLY, Phoenix, Arizona Email
    Custom Tuning Services
    DURAMAX/CUMMINS ECM's TCM's for sale, all years, 20% wholesale discount available
    EFILive's first VGT "Software Wastegate Tune"

  5. #5
    Lifetime Member Dmaxink's Avatar
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    This would open up a whole new world if evilive could make it happen...I would be above grateful! Lol
    -Kory

    I'm out of ideas? Nah trick... When in doubt, 0xFFFF it out!

    http://www.PPEI.com/

  6. #6
    Lifetime Member LB72004's Avatar
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    just reading over this thread, found it interesting.

    wondering if it was not possible or no one was willing to do it from programming, what about a mechanical solution? could every other tooth on the rings/cogs the slip sensors monitor get filed down so as to create only half of the pulses, tricking the transmission into thinking it is slipping at 300 RPM when it is really 600. this would of course require adjusting some of the tables in the trans tune to make it lock up and shift smoothly under light driving but this is small compared to everything else needed to be done.

    Jason

  7. #7
    Lifetime Member vortecfcar's Avatar
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    The 'slip sensor' is just a pid that subtracts ISS from engine RPM. Grinding teeth off of trans parts will lower the ISS value and take you further (not closer) from 600.

    It's not an easy problem to solve without calibration access. There are several diagnostic hurdles when lying about shaft speeds.

  8. #8
    Lifetime Member killerbee's Avatar
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    I am only interested in knowing definatively if the slip limit is software linked.
    Michael, Systems Engineer 04.5 D-max LLY, Phoenix, Arizona Email
    Custom Tuning Services
    DURAMAX/CUMMINS ECM's TCM's for sale, all years, 20% wholesale discount available
    EFILive's first VGT "Software Wastegate Tune"

  9. #9
    Lifetime Member LB72004's Avatar
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    well that makes sense, still learning. not to keep beating around the same bush but i know there are sensors that put out two pulses for every tooth it senses. could this be of any use?

    Jason

  10. #10
    Lifetime Member THEFERMANATOR's Avatar
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    Quote Originally Posted by killerbee View Post
    I am only interested in knowing definatively if the slip limit is software linked.

    Yes, this has been discussed at length several times and proven to be in the TCM tuning.
    1995 GMC 2500 SUBURBAN powered by 01 DURAMAX/ALLISON, little of this, a little of that,
    DIAMONDEYE 4" exhaust, CORSA muffler, AFE stage 1 dry filter, custom tuning by me, KENNEDY single pump and pump rub kit.

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