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Thread: Some help with my 2-3 shift: towing mode

  1. #1
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    Some help with my 2-3 shift: towing mode

    I was hoping someone could give me a hand with this one. File attached.

    In tow/haul mode at about 32 - 40% tps I have a very sloppy 2-3 shift. It is tune related, aka something I've done as it does not happen with the factory tune or out of tow/haul mode with the same tune.

    I'm sure it is obvious but I'm just not seeing what I've messed up. Here is the scenario.

    Between 32 and 40% tps, about 40 - 45 mph when it goes to shift if feels like the following is happening. All this happens within a second or two.

    1. The TC disengages, rpms go up
    2. The shift to 2-3 happens but is very soft and slow
    3. The TC engages, rpm's go back down.

    My 1-2 shift is real quick and firm, no slop.
    If I go out of tow haul mode the 2-3 shift is real quick, could be a little firmer.

    I'm just not seeing what I dinked.

    Thanks for any feedback.

  2. #2
    Senior Tuner Russ K's Avatar
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    Your tow/haul 2-3 & 3-4 shift pressures are lower than the normal shift pressures.

    Post your stock tune.

    Russ Kemp

  3. #3
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    Thanks Russ, I always appreciate the help.

    Sorry for the delay, we are in the middle of yet another Disney trip. She towed nice except for the 2-3 shift.

    I took a quick look at my factory file and the pressures are the same, however I think I may have found my goof. I have the TC release speed in 3rd lower than where I come out of second gear.

    I'm going to put the factory release speeds back in the table.

    I still welcome your input. Going to be a few days before the vacation ends before I can test.

    One more final question, if I may. I live in very flat area of Florida. What do you think about adding TC lockup in normal mode for second gear?

    I hope all has been well.

    Hank
    Last edited by FGCUhank; 02-28-2009 at 03:31 PM.

  4. #4
    Senior Tuner Russ K's Avatar
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    Make the changes to the shift pressures & TCC lock up speeds as shown.

    Did you install taller than stock tires? Is your speedo accurate?

    Russ Kemp

  5. #5
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    Hi Russ,

    Sorry I missed this reply. My tires are "factory size" but based on the manufacturer specs they are 1" larger than the prior brand. I put some stock sized BFG AT's and a 2" lift kit on the van.

    I made the adjustment in the speedo settings for tires size and it is very accurate to my GPS.

    I'll make the changes you recommend and post back.

    Thanks again.
    hg

  6. #6
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    Hello Russ, Thanks again for the help with this. I have keyed it all in and am loading it in the am.

    Since you are the expert here, I have a question regarding the TCC settings for performance.

    I notice you pulled all the TC lockup out of second gear. Why did you choose to do that?

    Note: the factory program also had TC lockup in second gear but had that same sloppy 2-3 shift feel that started this thread.

    Thanks for the input.

    Ok, a second question, when I'm not towing and throw the towing switch the van really comes off the line and the TC lockup in 2, 3 and 4 really pulls good. Any logic why not to put TC lockup in 2nd for normal driving?