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Thread: 2004 GMC 6.0 4L80E & manual Transfer into 1978 Ford F-100...Trans????'s

  1. #1
    Lifetime Member GAMEOVER's Avatar
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    Smile 2004 GMC 6.0 4L80E & manual Transfer into 1978 Ford F-100...Trans????'s

    Everything went in smooth, got the 4X4 low & Hi working...motor is plenty for off-roading, sand duning e.t.c
    Finally got it on the freeway and that's when Problems started happening... The original HD truck came with 29" tall tires with 4.10 rear/front gears, the Ford F-100 has 32" tall tires with 3.50 gears...For some reason it won't stay in overdrive, it keeps downshifting to 3rd gear, sometimes into 2nd gear...If I manually shift thru the gears it shifts really good, but if I put it in drive and let it shift by itself, the tranny hesitates from 2nd to 3rd and to 4th. In the tune, I made changes in the speedo calculator that it has 3.50 gears and 32" tall tires but didn't fix the downshifting or hesitation...
    A buddy of mine told me my problem is the Torque Converter apply and release speeds? Could it be? I have never adjusted the TCC at all....
    The transmission only has 47,000 original miles

    Any help or guidance will be appreciated...
    2008 2WD Ext.Cab Silverado 1500 6.0 V-MAX E38(L76) & T42(4L70E) MAF Only CL Corvette Servo AFE CAI INNOVATIVE LM-2 WBO2

    FLASHSCAN V2 & AUTOCAL

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    This may be a stupid question, but you said you adjusted the speedometer, but did you also adjust the shift speed tables? Those speeds will still be off since they were originally choosen based on the 29" tall tire and 4.10's.

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    Lifetime Member tokymon's Avatar
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    in the speedo calculator you can go to a tab that says shift point correction make sure to hit apply the also
    97 2500 ecsb 5.7l/4l80e/4x4 411 pcm /thorley tri-y's/dual super 40's with x (catless)/aem cai/msd 6a and coil/zz4 cam/beehive spring/lm-1

    stock sucks

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    Lifetime Member GAMEOVER's Avatar
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    I've never used the shift point correction, Just tire height and rear end gear ratio....Opened up the tune set tire height and gear ratio back to stock, also added new tire height and gear ratio's, I hit the apply button and it pretty much changed everything that I needed....
    2008 2WD Ext.Cab Silverado 1500 6.0 V-MAX E38(L76) & T42(4L70E) MAF Only CL Corvette Servo AFE CAI INNOVATIVE LM-2 WBO2

    FLASHSCAN V2 & AUTOCAL

  5. #5
    Lifetime Member GAMEOVER's Avatar
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    Didn't work....Well i guess tranny is going to an expert!....
    2008 2WD Ext.Cab Silverado 1500 6.0 V-MAX E38(L76) & T42(4L70E) MAF Only CL Corvette Servo AFE CAI INNOVATIVE LM-2 WBO2

    FLASHSCAN V2 & AUTOCAL

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    Hello Gameover,

    Sorry to hear it didn't work out. Post (or send me) the tune if you want - sometimes a second pair of eyes picks up something initially overlooked.


    Regards,
    Taz
    Last edited by Taz; March 14th, 2012 at 01:06 PM. Reason: - typo

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    Lifetime Member GAMEOVER's Avatar
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    Ok here's the file, this is after the shift point correction that EFI Live does...
    2008 2WD Ext.Cab Silverado 1500 6.0 V-MAX E38(L76) & T42(4L70E) MAF Only CL Corvette Servo AFE CAI INNOVATIVE LM-2 WBO2

    FLASHSCAN V2 & AUTOCAL

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    Hello Gameover,

    Some of the part throttle downshift speeds were greater than their corresponding upshift speeds - this would make the shifts erratic at best. Give the attached tune a try - it uses stock 2002 LQ4 4L80 shift speeds - adjusted for 32 inch tires and 3.50 gears. No other changes were made to the tune.


    Regards,
    Taz

  9. #9
    Lifetime Member tokymon's Avatar
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    There's a spreadsheet on here for shift points you can map upshift and down shift as well as tcc lock and unlock .
    I'm not home to post it but just search you should find it
    97 2500 ecsb 5.7l/4l80e/4x4 411 pcm /thorley tri-y's/dual super 40's with x (catless)/aem cai/msd 6a and coil/zz4 cam/beehive spring/lm-1

    stock sucks

  10. #10
    Lifetime Member GAMEOVER's Avatar
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    We'll after 2 weeks of diagnosing and a semi-rebuild of tranny...I figured out what it was...
    2008 2WD Ext.Cab Silverado 1500 6.0 V-MAX E38(L76) & T42(4L70E) MAF Only CL Corvette Servo AFE CAI INNOVATIVE LM-2 WBO2

    FLASHSCAN V2 & AUTOCAL

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