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Thread: destroked Allison stand alone kit will not go into tow haul mode

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    Default destroked Allison stand alone kit will not go into tow haul mode

    Hi i have a 1997 F350 crew cab 7.3 powerstroke with a destroked Allison stand alone setup. The Allison works fine but will not go into tow haul mode never has, have sent computer back and told all working fine is a pian as i have converted it 6 speed and have to keep changing computer to tow is there anything i can check the light on the column comes on but no shift and still goes in sixth, my other problem is i live in Australia any help would be appreciated

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    Lifetime Member THEFERMANATOR's Avatar
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    Need to know exactly what all you have done to it. You say you have the detroked kit, but then say a 6 speed. Does it also have a SUNCOAST 5-6 speed conversion kit in it? There are 2 distinctly different p[latforms for the 5 speed TCM's, the 01-02 and the 03-05. 01-02 used the class 2 data bus to engage tow/haul mode but you had to have the latest flash to get the overdrive lockout which worked directly through the TCM. 03-05 uses the class 2 data bus for both signals. If you have put in a SUNCOAST kit, you may have the wrong 5-6 speed conversion platform and it may not communicate properly as I believe the destroked kit uses an 03-04 LB7 TCM operating system. If you have swapped in a gen IV TCM from an 06+ truck, then I don't believe teh DESTROKED kit will work as they are CAN BUS based.

    Need to know exactly what you have as far as TCM goes and operating system in it. And have you contacted DESTROKED about this and talked with them? Maybe you need to talk to the folks at PCS since it is there XFC box that DESTROKED uses and I believe they wrote the software for it as well.
    1995 GMC 2500 SUBURBAN powered by 01 DURAMAX/ALLISON, little of this, a little of that,
    DIAMONDEYE 4" exhaust, CORSA muffler, AFE stage 1 dry filter, custom tuning by me, KENNEDY single pump and pump rub kit.

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    it has never ran even with the destroked computer i have been in contact with them and they don't know what to do. Yes it is a suncoast 6 speed kit
    Last edited by zrinch; October 22nd, 2011 at 05:58 PM.

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    Does it work with a stock 03-04 TCM? Does overdrive lockout work? I doubt DESTROKED designed there kit to work with a modified TCM like teh 6 speed conversion kit uses. You should see a distinct difference in the shifts between normal mode and tow haul mode. In normal mode you shouldn't get lock-up until 5th gear under normal acceleration, but in tow/haul mode you will get lock-up in 2nd as well as raised shift points. What TPS set-up are you using since your 97 PS is a drive by wire system? You need to find somebody with EFILIVE or a TECH2 to scan your data port for the TCM to see if teh TCM is reading the correct data from the XFC box and go from there. I don't know what software DESTROKED includes with there kits, but I believe all they do is use a PCS XFC box to emulate the DURAMAX's ECM TPS signal and send that to the TCM via the J1939 data bus. And I believe they also tie into the J1850 data bus for tow/haul mode and diagnostics. Also you may try contacting Brayden at Fleece Performance as he is pretty well versed in the ALLISON TCM and it's inner workings.
    1995 GMC 2500 SUBURBAN powered by 01 DURAMAX/ALLISON, little of this, a little of that,
    DIAMONDEYE 4" exhaust, CORSA muffler, AFE stage 1 dry filter, custom tuning by me, KENNEDY single pump and pump rub kit.

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    Thanks for your help the tow haul has never worked even with destroked 5 speed TCM I have send both the XFC and 6 speed TCM back and destroked have tried it, i was told it worked all ok for them but i can't work out why it does not work in my truck unless there is a problem with there wiring do you know which pin on the allison TCM recieves the info for tow/haul maybe there is a missing link. As i'm not getting much help from destroked. thanks again for your help

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    I really don't know much about there kit. I looked into them when I did my swap, and they didn't seem to know much about it either. There is always a chance you have a crossed wire somewhere in your harness as peopel do make mistakes sometimes. Ask them if they can email you a complete wiring diagram so you can trace it all out.
    1995 GMC 2500 SUBURBAN powered by 01 DURAMAX/ALLISON, little of this, a little of that,
    DIAMONDEYE 4" exhaust, CORSA muffler, AFE stage 1 dry filter, custom tuning by me, KENNEDY single pump and pump rub kit.

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