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Thread: 5 to 6 speed conversion

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  1. #1
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    Default 5 to 6 speed conversion

    anyone know how I would go about this? or am I forced to buy a locked TCM? I doubt a simple OS re-flash would do it.

    Yes I have a valve body.

  2. #2
    Lifetime Member THEFERMANATOR's Avatar
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    If you have a 01-05 DURAMAX truck with a 5 speed and want to make it a 6 speed, you are pretty well limited to the SUNCOAST kit. The 6 speed valve body will not just drop into a 5 speed and then have a 6 speed OS flashed in(tried this). You have to use the 5 speed style solonoids which means you have to run the kit. And if it is a 01-05 truck, there is no factory or ALLISON flash to enable 6th gear. If you have an 06-07 MD with a 5 speed, then yes it can be flashed to a 6 speed by ALLISON, or if you have a 8.1L you can swap in an 06 TCM, 6 speed valve body, modify the wiring harness, and have a 6 speed.
    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.

  3. #3
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    Default allison 5 speed to 6 conversion ?? 2006 Topkick 4x4

    Quote Originally Posted by THEFERMANATOR View Post
    If you have a 01-05 DURAMAX truck with a 5 speed and want to make it a 6 speed, you are pretty well limited to the SUNCOAST kit. The 6 speed valve body will not just drop into a 5 speed and then have a 6 speed OS flashed in(tried this). You have to use the 5 speed style solonoids which means you have to run the kit. And if it is a 01-05 truck, there is no factory or ALLISON flash to enable 6th gear. If you have an 06-07 MD with a 5 speed, then yes it can be flashed to a 6 speed by ALLISON, or if you have a 8.1L you can swap in an 06 TCM, 6 speed valve body, modify the wiring harness, and have a 6 speed.

    I have been considering purchase of a 2006 Topkick 4500 4x4 engine decodes as an LLY and guy says trans is a 5 speed you mentioned that 2006 MD can be flashed to enable use as a 6 speed who do I need to contact or what needs to be done to have this update done when or fi the get the truck

  4. #4
    Lifetime Member killerbee's Avatar
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    Quote Originally Posted by motorhead540 View Post
    I have been considering purchase of a 2006 Topkick 4500 4x4 engine decodes as an LLY and guy says trans is a 5 speed you mentioned that 2006 MD can be flashed to enable use as a 6 speed who do I need to contact or what needs to be done to have this update done when or fi the get the truck
    For 06 and 07 MD trucks, it is not practical to simply reprogram your TCM, but we have a service that exchanges your 5-speed TCM for the 6-speed coded TCM you are needing. It is a straight forward swap process.
    Michael, Systems Engineer 04.5 D-max LLY, Phoenix, Arizona Email
    Custom Tuning Services
    DURAMAX/CUMMINS ECM's TCM's for sale, all years, 20% wholesale discount available
    EFILive's first VGT "Software Wastegate Tune"

  5. #5
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    sent you an email for 6 spd TCM on my lly.

  6. #6
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    Quote Originally Posted by killerbee View Post
    For 06 and 07 MD trucks, it is not practical to simply reprogram your TCM, but we have a service that exchanges your 5-speed TCM for the 6-speed coded TCM you are needing. It is a straight forward swap process.
    Hey, killer bee, do you still offer this service? I need an al5 tcm with unlocked 6 speed calibration without core.

  7. #7
    Lifetime Member killerbee's Avatar
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    Quote Originally Posted by Lennydmaxguy View Post
    Hey, killer bee, do you still offer this service? I need an al5 tcm with unlocked 6 speed calibration without core.
    Yes, I have a few of these. You can use the email in my signature.
    Michael, Systems Engineer 04.5 D-max LLY, Phoenix, Arizona Email
    Custom Tuning Services
    DURAMAX/CUMMINS ECM's TCM's for sale, all years, 20% wholesale discount available
    EFILive's first VGT "Software Wastegate Tune"

  8. #8
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    Hmmm...OK... I get what you are saying about the solenoids, makes sense.

    It's an 02. Access to various VBs is not an issue, but, without that software for the G solenoid, I'm SOL...

  9. #9
    Lifetime Member THEFERMANATOR's Avatar
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    The G solenoid has nothing to do with the 6 speed as the SUNCOAST 5-6 speed kit doesn't use it(but they do use a G solenoid type valve body). The problem is having the 6th gear pipe installed in the valve body which means you have to start with a 04-05 5 speed valve body to be able to install one. Then you have to have the software to command the extra shift of the C2 and C4 clutch pack for 6th gear. ALLISON has the TCM OS, but they won't pass it up and I doubt it is even on there servers for download if you had access to the ALLISON DOC. For an 01-05 to get 6th gear, your only option is the SUNCOATS kit if you want everything to work like stock(some have installed a GEN IV 6 speed TCM and made the other changes, but it still won't work as designed as the GEN IV TCM will be working in default mode without receiving the GM high speed can bus data protocol messages from the BOSCH ECM). I looked into this myself last year(even bought the 6 speed valve body and associated components) to only find out the software was a hurdle not easily overcome.
    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.

  10. #10
    Lifetime Member LB72004's Avatar
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    what about the cost (suncoast kit) vs the benefits? is it worth it? do you get that much better MPGs????
    2008 Chevrolet 3500HD DRW LTZ
    285/75/17 Nitto Dura Grapplers, 4.56 gears, Front and rear ARB lockers, Efi Live tuning by me, Raptor 160 LP, Cognito 4-6 NTB Lift, 4" Exhaust, Built Trans by Mike L.

    Sold - 2004 LB7 Duramax, EFI Live with DSP5 Tune
    stage 4 SC transmission, 265/70/16 tires

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