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Thread: 8l90 TCC regulator offset not working

  1. #1
    Potential Tuner
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    8l90 TCC regulator offset not working

    I am trying to increase the minimum TCC pressure to stop the torque converter from slipping
    i have read that the regular offset will set the minimum pressure, i have tried increasing the offset and the gain am i missing something or is there another way to do it?

    tcm os is 24274897

  2. #2
    Advanced Tuner
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    Bringing this back up, since I experienced the same thing as the OP it doesn't do anything. I've never really messed with a 6L80 but I believe adjusting the gain and offset like this was how 6L80 people adjusted torque converter pressure.

  3. #3
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    Quote Originally Posted by cmitchell17 View Post
    Bringing this back up, since I experienced the same thing as the OP it doesn't do anything. I've never really messed with a 6L80 but I believe adjusting the gain and offset like this was how 6L80 people adjusted torque converter pressure.
    How much slip are you getting? TCC slip is closed loop on the desired slip, so if it is slipping too much, the trans should be trying to correct it. Adjusting offsets is sort of a bandaid...really have to just target less slip or disable the feature. Post a file and I may be able to help.

  4. #4
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    I was commanding 0 slip and it was holding but because the TCC is closed loop it would lower the pressure until it slipped then would increase the pressure again and lock up. I was trying to prevent this cycling with the offset.(basically disable the closed loop by setting a minimum pressure)

    I think this is a tuning issue from the factory and what is causing the TCC shudder, I replaced the converter, refilled the trans with Mobil 1 synthetic lv atf hp fluid, put the slip tables back to stock and it was better but not gone.

    I sold the truck after I swapped torque converters but I still should have some log files and the tune that I can post. I?ll have a look tonight

  5. #5
    I am dealing with this as well. I had to set my gain to 0 and my offset to 90 to get ~50 psi initial pressure on my tcc and it still slips under light load but not like it was and i can finally use 7th and 8th gear at a steady cruise speed without feeling like its gonna burn up the tcc. I would still like about 30psi more at all times but i just dont think its gonna happen. I took the offset up to 115 and it seemed to have a negative effect when compared to having it set at 90. Tcc ramp also doesnt do what i expect it to when adding pressure.

  6. #6
    Quote Originally Posted by smokeshow View Post
    How much slip are you getting? TCC slip is closed loop on the desired slip, so if it is slipping too much, the trans should be trying to correct it. Adjusting offsets is sort of a bandaid...really have to just target less slip or disable the feature. Post a file and I may be able to help.


    Im sorry i must have missed this comment. Yes any help at all would be greatly appreciated. There is a log and a tune file on the latest post i started here:

    https://forum.hptuners.com/showthrea...ply-ramp-table

  7. #7
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    https://forum.hptuners.com/showthrea...light=8l90+tcc

    We were missing a table - TCC Desired Pressure.

  8. #8
    Senior Tuner
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    I had the same issue with my 6L90 and support first added the use regulator settings switch which allowed me to use the reg offset and gain. Then later on support added the desired pressure table.

    Definitely get in touch with them. Also, download the latest beta just to see if it is already in there. It will be there first before it makes it to the production build.