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Thread: 1994 tbi 454 4l80e transmission tuning/tcc lock up in 2nd

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  1. #1
    Carb and Points!
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    1994 tbi 454 4l80e transmission tuning/tcc lock up in 2nd

    Hello there, been playing with my transmission settings to get lock up in 2nd gear and hold lock up a bit better in 4th gear/handle more tps% before unlocking tcc. This is a motorhome application that we pull a trailer with most the time. Hoping 2nd gear lock up will help transmission temps while in the hills at slow speeds. Also wondering if anybody has been able to keep the converter locked when off the throttle in 4th gear at spds. I love the way my Allison transmission works in my pickup, would be nice if I could use some of the same features like they do with the tcc. I have managed to get lock up in second and turn up line pressure in second due to feeling it shudder after activating tcc in 2nd. But now I have a bit of a shift flair going in to third. Long story short I am using tuner pro and was hoping someone could turn me on to some 4l80e towing/2nd gear tcc lock up bins to get a idea/campare. I appreciate any info that is out there. Thank you

  2. #2
    Fuel Injected!
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    What bin and mask are you using?

    Are you keeping the torque converter locked during the 2nd -> 3rd shift? Have you modified the target shift times? I would have to look but I seem to remember that the code will first unlock the TCC before starting the shift unless you have it set to keep the TCC locked during a shift. I think that would feel like shift flare since the rpms would rise before the shift even starts. I have my 4l60e setup to stay locked during the 3rd -> 4th shift and it seems to work fine. I also have it staying locked in 4th with closed throttle up to a certain speed. I do remember it took a few tries to get that to work, I think there may be some poorly described settings in the xdf relating to that, but I'm probably not using the same xdf as you. I am using $E6.

  3. #3
    Carb and Points!
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    I am using $0E Mask and my stock bin. Yes the tcc was staying locked 2-3 shift. Don't know why 2-3 shift locked is so much worse than 3-4 when locked. But after a few trial and error I set my tcc unlock spd to 1mph below the 2nd gear upshift scale and no more shift flare. I have only modified my shift times in 1-2nd shift. What did you adjust to keep lock up at 0% throttle? Thank you for you reply

  4. #4
    Fuel Injected!
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    I have 94/454/4l80e/OE also. I have modded my shift speeds and lockup speeds slightly to fit in with local speed limits. I then tried to replicate tow haul. It worked but not as well as I would like. I put in a dpdt switch and wired one side as normal and the other side manual. Now when I tow I use manual and can lock it when ever I want. That also allows lock in 0 throttle compression. When mine was stock it would only lock in 4th after 56 mph.
    6395, BHDF, 7.4 BBC lightly modded now 6395 BMHM back to BHDF

  5. #5
    Fuel Injected!
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    It looks like I raised Upper/Lower " MPH for Using Low Speed TPS Thresholds" from 38/36 mph to 48/46 mph along with Upper/Lower " Low Speed TPS to Prevent Repeated TCC Cycling" from 2/4 to 0/0. Setup that way I still get unlock in 4th above 48 mph below 5% throttle, but no unlock at zero throttle below that speed. I'm not sure about the 4L80E but the 4L60E doesn't have an overrunning clutch in 4th gear so closed throttle with TCC locked at higher rpms will result in a lot of engine braking. If you never wanted it to unlock at low TPS you could just lower the TPS thresholds for Upper/Lower Low/High Speed " To Prevent Repeated TCC Cycling" and leave the MPH ones alone.

    Of course this assumes that those parameters are supported by $OE...

  6. #6
    Fuel Injected!
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    I have a Merry XMISH present for you.

    Check "LOW TPS TCC CYCLING PREVENTION" and the two tables below it.
    Attached Files Attached Files

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