Results 1 to 10 of 10

Thread: 8L90 tuning - how to get TUTD to automatically shift at WOT

  1. #1
    Tuner
    Join Date
    Dec 2019
    Location
    Boerne, TX
    Posts
    117

    8L90 tuning - how to get TUTD to automatically shift at WOT

    Any of you with the L86/8L90 know that 1st gear redline comes pretty damn quick from a roll. I have to roll because 1st gear is almost useless in 2wd. Add traction loss and it gets worse. Add the stupid delay between clicking it into 2nd and now it's just dumb. I bounce off 1st all the time then it finally grabs 2nd and I basically have to click it into 3rd right away again.

    So, I've been trying to get TUTD to work better but I keep coming up empty. I'm trying to get it to automatically shift into 2nd and so on so forth. This will let me roll it out and hold first as long as I want and then when I hammer it it'll shift automatically.

    Anyone know how to do it? I've tried adjusting all the corresponding TUTD/Pattern A/Pattern B/Normal tables to all match and still - nothing.

  2. #2
    Have you searched camaro6 before? It?s not a truck OS so I?m not sure how much applies to your application.

    https://www.camaro6.com/forums/showt...php?p=10640039

  3. #3
    Tuner
    Join Date
    Dec 2019
    Location
    Boerne, TX
    Posts
    117
    Quote Originally Posted by jasonz28camaro View Post
    Have you searched camaro6 before? It?s not a truck OS so I?m not sure how much applies to your application.

    https://www.camaro6.com/forums/showt...php?p=10640039
    Thanks for the help bud! Yes I did stumble upon that thread and tried and tried to no avail. Same engine and trans but I guess, like you said, the os is different enough to not work on my truck. Oh well. I just play around in tow/haul now. On that pattern I have the part throttle shift points set pretty high so I can at least roll out.

  4. #4
    Advanced Tuner
    Join Date
    Aug 2014
    Location
    Central, LA
    Posts
    737
    All you've got to do is set the 100 column and the tutd wot shift speeds accordingly and it should shift.

  5. #5
    Tuner
    Join Date
    Dec 2019
    Location
    Boerne, TX
    Posts
    117
    Quote Originally Posted by sevinn View Post
    All you've got to do is set the 100 column and the tutd wot shift speeds accordingly and it should shift.
    You've done this on a truck?

    Yep, that's exactly what I've done. I've made them all correlate perfectly and still nothing.

  6. #6
    Advanced Tuner
    Join Date
    Aug 2014
    Location
    Central, LA
    Posts
    737
    Quote Originally Posted by lucas287 View Post
    You've done this on a truck?

    Yep, that's exactly what I've done. I've made them all correlate perfectly and still nothing.
    Oh I've missed that it's a truck sorry, no I've never been successful on a truck trying to make tutd shift.

  7. #7
    I’m interested if anyone has done it on a truck too? I have a swap car with 2018 Tahoe OS with a 10 speed. At the moment I cannot even shift at high rpms while doing tapshift, I may be able to adjust some stuff but the truck os doesn’t play well.

  8. #8
    Potential Tuner
    Join Date
    Sep 2016
    Location
    Michigan
    Posts
    7
    I've spent a lot of time working on the shift timing on my 2015 Yukon Denali. I finally have it perfect, easy on the gas and you don't even feel it, hammer it and it gets rubber in 2nd with 33's and sometimes in 3rd. It shifts exactly where I want it when I want it. For as many complaints as I've heard about this tranny, it works perfect for me. I did have the torque converter replaced and went to Amsoil trans fluid. The Amsoil got rid of the torque convertor release issue at decel. I've been trying to figure out how to upload my tune to share it. I find the command delay in the TUTD makes it to unpredictable to use at all.

  9. #9
    Advanced Tuner
    Join Date
    Apr 2016
    Posts
    328
    Same issue with the 6 speed truck trans, the tap shift is very slow (read: bang on the rev limiter!). Probably why the OP wants it to upshift on its own.

  10. #10
    Tuner in Training
    Join Date
    Feb 2023
    Posts
    24
    I know this in an old thread, but would you mind posting your file?