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Thread: Lock TCC @ WOT?

  1. #1
    Advanced Tuner n0dih's Avatar
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    Lock TCC @ WOT?

    I have a L29 454 Suburban (1999) and the stock and tuned PCM locks the TCC @ WOT.

    Is there a reason WHY one would want to do this? It sucks if you ask me.

    Does anyone have any experience with tow mode or trucks that do or don't lock TCC at WOT?

    Thanks!

  2. #2
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    I just looked at a 2000 L29 cal in a duley truck and a 99 L29 cal in a 99 4x4 truck and both cals keep the converter locked at WOT. They even lock it up from 87-100% TPS in 2nd gear. Never noticed that before and not sure why but easy to change if you don't like it. Now I'm wondering what kind of lock up clutch GM put in those converters that will hold WOT lockup behind the torque output of a big block. I don't think the 2 trucks I have cals for had tow/haul mode on them. On trucks that do have tow/haul mode, those tables usually just keep the truck in gear longer before shifting and up the line pressure a bit.

  3. #3
    Advanced Tuner n0dih's Avatar
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    Got any 8100 cals to look at? What do they do? Do the DMax trucks lock TCC at WOT?

    Tow/Haul never existed on the 454 trucks, but GM did do a "Towing Improvement Program" on the latest software release of the tune. It won't even lock up TCC at light throttle until 68 mph. In 3rd or 4th.

    Really needs a lot of fixing if you ask me. I am not too thrilled with it being I tune my LT1 Fleetwood and it drives like a dream. I have a lot of work to do on the 454 truck when I get a tuner program (still working on that....)

    Look at 2nd gear, it even locks up in 2nd!

  4. #4
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    The L18 8.1L locks up at WOT too, but not in 2nd gear. It appears to have tow/haul tables. (performance mode) What are you using to tune your LT1 and what year is it?

  5. #5
    Advanced Tuner n0dih's Avatar
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    TunerCat, for 94-95 LT1's. Old School OBD1.... Mine is a 94 Fleetwood.

    How good? Well, I like hunting Dodge Hemi Rams with my Fleetwood...

    That thing got a Hemi??? HAHAHAHHAHAHAHAHAHAHA

    With my factory 3.42's I can take them from 0-100 mph and keep pulling on them.... That isn't any 345 hp engine. Vehicle weight is similar and they have better gears. I have better aero. I call it a draw, but I still can take em.... Maybe if they mod it they can take me, but stock to stock, I can take them.