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Thread: 17 Silverado 5.3 A6 - Shift pressures or adapt presets?

  1. #1
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    17 Silverado 5.3 A6 - Shift pressures or adapt presets?

    This all started with me rebuilding a 6l80 once a week due to torque converter clutch failure. I have disabled AFM getting rid of the 40RPM ECCC slip. also have lockup in 4-5-6, 3rd at very light throttle. also have taken the 20rpm slip out at higher torque zones. 2 questions:

    1: I occasionally get a "fishbite" when the torque converter is trying to reach 0 slip. 0-12 rpm slip is seen when this happens. From my understanding the software tries to figure out exactly how much pressure it takes to hold 0 rpm slip which in my opinion causing this "fishbite" feeling and causes torque converter clutch flaking.

    2: I cannot figure out how to control the shift firmness. the stock tune has the 1-2 shift very soft and delayed as to give the converter a chance to lock as soon as it hits 2nd. I cannot get the 1-2 shift correct. also the 2-3 shift is a little off causing a very slight "clack" at light throttle upshift.

    Again, my truck is completely stock. I am only trying to make the converter last longer that 90K miles and of course drivability. locking the converter in 2nd(stock tune) causing poor acceleration and will also burn the converter clutch at mid throttle. Lastly I disabled WOT lockup.

  2. #2
    Tuning Addict 5FDP's Avatar
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    I disabled the torque converter in all gears expect 5th and 6th as well as raising the mph shift speeds up for each gear. I don't allow 6th until right around 50mph.

    I think this tune of mine is fairly recent, it's from a 2016 truck so the tables should be very very similar.

    It's mainly shift time changes, shift pressure changes and on-coming pressure preset changes to make it do what I want.

    If you have questions on what I did, just ask in this thread with specifics or screen shots so I can know what you are asking about.
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    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

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    Thank you for your reply. GM actually changed the trans tune quite a bit from 16 to 17 but I am comparing yours to a stock 16 tune to see what you did. Will study it closer over the weekend. I see that you did not change the TCC desired slip, maybe that is why I am getting the "fishbite". Also am curious how many miles you have put on the truck since leaving your converter unlocked. I have been told that going old school and leaving the converter unlocked too much can cause damage since the 6L80 was never designed to leave converter unlocked except for launch and shifting. Thanks again for your help

  4. #4
    Tuning Addict 5FDP's Avatar
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    My two previous trucks were a 2010 and a 2012, if I remember right they only locked the converted in gears 3-6 but changed it to every gear in the 2014+ trucks with DI and torque based controllers.

    The 2012 I bought used I put like 16k miles on it with it locked in 5th and 6th only and the 2016 I have now that I also bought used it's been about 5,000 miles with 5th and 6th lock up only. Haven't have any issues at all.

    With what I've done and the E85 I used this past summer, it drives pretty awesome for being nearly all stock.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  5. #5
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    5FDP - Do you find it better to just modify the main multipliers like you did vs dialing in the pressures and everything? I only ask because I've been after a quick shift without banging gears... Still working out the best route, but have tried a few different ways over the years and never really settled on one I really like other than dialing in individual pressures with most of the tm gone... Anyhow I was just wondering...

    This is another decent trans tune - it's pretty much just a modified diablo firm shift

    I've also found that lowering slip speed on the tcc will usually cause more shudder, so I stopped that a while back... As cheap as these converters are made I really believe it's inevitable that the converter will fail - I understand what your after, but getting a little more life will probably be about it...
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    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    No Longer with passion performance auto for good reasons

  6. #6
    Tuning Addict 5FDP's Avatar
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    I've always like to just lower the shift time (torque adder) to a certain point and from there messed with the main upshift pressure for the specific pattern and on-coming pressure presets to get what I was after. Sometimes I've lowered the torque factor in the TM tab but rarely more than 10-20%.

    Doing it that way gets me nice clean quick part throttle shifts without is ever jolting into gear or having a weird long pause for going again.

    Does that sorta help with the question you were wondering about???



    I'm sure if I did more side work and got to see more modded vehicles I could work with different ways. Though even with few people I've helped that have trucks with power adders, the same style of changes have been good.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  7. #7
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    Thank You. I've been playing with my own truck, but it's a diesel, so the extra torque makes a big difference on dialing this thing in I'll give your method a try as soon as I get some time...
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    No Longer with passion performance auto for good reasons

  8. #8
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    This is just another example on tuning in your shifts. I've been spending a lot of time on this one and still have a touch more to go - it's my personal truck, but this one should help you see how the tables are used or correspond to one another. I tried the settings in the other tune, but I guess my diesel just has too much torque with them - it had a lot of shift flare that actually put it into rep on a wot pull and shut the engine off completely :/ Was afraid that might happen... I'll play with it some more, but I think this trucks operating system is just odd enough for it to not work - for example it shifts softer with tm disabled than it does with it enabled...

    The tune I posted above can be completely copied over to your truck other than you might want to lower timing 2 or 3 degrees - it's a 93 daily driver...
    Attached Files Attached Files
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    No Longer with passion performance auto for good reasons

  9. #9
    Tuning Addict 5FDP's Avatar
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    The gas to diesel difference I'm sure does make it different like you said. I've never worked on a diesel truck with the 6L80e before.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  10. #10
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    It's not a 6l80 - just the same pos that they slightly upgraded from their regular v6 Colorado's It acts screwier than any transmission I've ever tuned before - pretty sure it's got mechanical issues/design flaws with greatly differentiating clutch pack clearances making things very hard to adjust.