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Thread: Adjusting Allison Shift Times

  1. #1
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    Default Adjusting Allison Shift Times

    Has anybody played with this? Is there a minimum time to keep? What are the risks involved in shortening the times? Why do the desired shift time throttle adjust values start to increase in the upper tps% on the 3>4 and 4>5 shifts? Is there a reason not to adjust these values to shorten the shift times?

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    i know on the 3-4 up shift the on coming and off going clutch packs are right near each other and they tend to tie up under higher hp combo's. i believe they must have saw this from the factory and to prevent it they just added a few milliseconds to the shifts. as the power goes up the tcm can't prevent it even with the added timing. it is not a pleasent feeling the 3-4 shift. that is also why they have the defuel integrated into the calibration.

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    Quote Originally Posted by stacks04 View Post
    i know on the 3-4 up shift the on coming and off going clutch packs are right near each other and they tend to tie up under higher hp combo's. i believe they must have saw this from the factory and to prevent it they just added a few milliseconds to the shifts. as the power goes up the tcm can't prevent it even with the added timing. it is not a pleasent feeling the 3-4 shift. that is also why they have the defuel integrated into the calibration.
    Shouldn't this be exactly the opposite? Shouldn't they be making the shift times shorter to prevent slippage? From the reading that I have done on this subject, it appears that the reasoning behind it was to make the shifts softer. I want to make them shorter so there isn't as much chance to slip.

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    Send me your ECM tune and I will make some changes to it that makes it shift like a ATS Co-pilot.

    You dont want to shorten the shift as you could bind the shifting and ruin the build! I have a built trans and still shifted the same, thats the function of the adaptive shifting.

    Send me the basics of your truck like built trans, engine mods and I will help to adjust the tune to your trans and get it to the point that you are happy about the way it shifts.

    Tony
    Armdist@yahoo.com
    Mine2001 GMC 2500HD EC/LB, D/A. 4in MBRP exhaust, AFE Stage II w/Amsoil Ea air filter, ISSPRO boost/Pyro guages, PPE Boost Valve, EFI Live V2, Maximum OD Stage 2 Trans, Amsoil throughout, AirDog150, modded intake horn.

    540HP/1056TQ
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    Hers: 2006 GMC Envoy XL Denali, Flowmaster 40 with a bullet style resonator in the back, EFI Live with the help of JoeCar and other great members here.

  5. #5
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    Quote Originally Posted by Sparky8370 View Post
    Shouldn't this be exactly the opposite? Shouldn't they be making the shift times shorter to prevent slippage? From the reading that I have done on this subject, it appears that the reasoning behind it was to make the shifts softer. I want to make them shorter so there isn't as much chance to slip.
    if you tune to defuel more than you can make them shorter. if not the more power the more of a chance you'll have a tie up. heva you driven one with the defuel turned off via the tcm tune. the 3-4 shift is a hard parts breaking shift with the stock shift timing. i can only imagine what it would be like in a higher hp truck with a quicker shift. the allison was not designed to shift like a turbo 350. adding the trans-go and or co-pilot only adds to the problem by making it shift quicker. the trans go does it hydraulic, and the co pilot does this electronically.

  6. #6
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    Duramaxtuner (Nick) has made me a DSP5 tune. I've made some tunes already myself. One tune I made I pretty much copied and it was only supposed to be a 100hp tune, but I added timing to it and reduced the defuel. I limped my tranny on that one. I made a more conservative tune and didn't reduce the defuel as much and it's a really good tune. I just figured I'd adjust this too so it didn't have as much of a chance to slip. I'm not too worried about breaking hard parts because it's not to bad right now.

    Oh, and I think you can disable adaptive shifting by reducing the shift times to zero, or at least I read that about other gm trannies.

  7. #7
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    Your trans and engine have two differant tunes! The TCM holds the tune for the trans and the ECM holds the tune for the engine. When you tune the engine you are not tuning the trans what so ever, so be careful about tuning the engine as you can put more power to the ground without getting things right in the trans.

    The best thing to do is to use the adaptive learning to your advantage, not shut it off. It is there so you dont shift like a old TH350 with a shift kit all day. I have a built trans and it still shifts nice and smooth like the factory build, except I have more clutches and a Trans Go. The adaptive learning/shifting is there to save the trans, use it.

    Tony
    Mine2001 GMC 2500HD EC/LB, D/A. 4in MBRP exhaust, AFE Stage II w/Amsoil Ea air filter, ISSPRO boost/Pyro guages, PPE Boost Valve, EFI Live V2, Maximum OD Stage 2 Trans, Amsoil throughout, AirDog150, modded intake horn.

    540HP/1056TQ
    Dyno'd Danville Performance
    April 5th 2011

    Hers: 2006 GMC Envoy XL Denali, Flowmaster 40 with a bullet style resonator in the back, EFI Live with the help of JoeCar and other great members here.

  8. #8
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    Quote Originally Posted by horsehaulin View Post
    Your trans and engine have two differant tunes! The TCM holds the tune for the trans and the ECM holds the tune for the engine. When you tune the engine you are not tuning the trans what so ever, so be careful about tuning the engine as you can put more power to the ground without getting things right in the trans.

    The best thing to do is to use the adaptive learning to your advantage, not shut it off. It is there so you dont shift like a old TH350 with a shift kit all day. I have a built trans and it still shifts nice and smooth like the factory build, except I have more clutches and a Trans Go. The adaptive learning/shifting is there to save the trans, use it.

    Tony
    Yes I know, but the torque reduction is in the ecm. The only tables in the tcm I was interested in adjusting are the shift times.

  9. #9
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    Quote Originally Posted by Sparky8370 View Post
    Yes I know, but the torque reduction is in the ecm.
    What about D5194,5195,5196,5197 in the TCM?
    2007 CC/SB 4WD, McRat EFI Live, Trans, Trans Cooler and C3 clutch oiling mod by Mike L., SD Sleeves, SoCal Diesel

    2002 CC/DRW 2WD, McRat EFI Live, Trans, Trans Cooler and C3 clutch oiling mod by Mike L., SoCal Diesel

  10. #10
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    torque reduction come from the trans, yes it is adjusted in the ecm but the requests are made from the tcm. if you limit it or turn it off that you do it in the trans. before the tables became available in the tcm you had to best match the torque limited injection quantity to your shift points and make it work. as far as clutches go there is very limited slip that occurs under power during a shift. the factory as far as i am concerned used the defuel to prevent parts breaking from the amount of torque they have stock. the only shift i'd worry about slipping under power is the 4-5. and it is much more relevant to discuss the slipping while under power in a gear. namely 5th gear.

    the slip during a shift over the long term will not hurt you nearly as bad as the cost of fixing a shift tie up because your timing was off.

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