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Thread: 6L80 1-2 shift shudder help please

  1. #1

    6L80 1-2 shift shudder help please

    I did a lot of reading before I attempted tuning my 6L. I think I have most things where I want them but one thing that is weird is the 1-2 shift. Sometimes at part throttle is studders, almost double pumps. Every time at WOT it does. Shift time measures .400. my 2-3 and 3-4 are pefect. .150-.175 shift times. Id be happy with a shift time at .200 or something and one that doesn't studder. Could somebody check my tune real quick and see if there is a table I missed or something different to try. Thanks.
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  2. #2
    Tuning Addict 5FDP's Avatar
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    Maybe just a personal preference but I think your on-coming pressure presets are too high. Then your part throttle shift speed times are too fast is some spots because it's 0.000s. Maybe make those the same as the higher rpm of .2500s. It's always a game with some of these cars.

    Always reset the adapts so it can learn your new changes.

    Also having a dialed in engine calibration is key too. Those being the MAF/VVE and have a smooth timing curve.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  3. #3
    I kept desired shift time at 0, put everything to .225 in torque adder. Seems to be hitting .250 on the 1-2 but still a little studder. Maybe lower my on coming pressure a bit? Also, what does desired output torque factor do? Thanks for your help!

  4. #4
    Also found a really good post about some things. Says to put none in the tip in tqmgt, flare tqmgt, and limit tqmgt. I don't understand fully what they do. But most are set to no throttle?