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Thread: 2015.5+ Allison TCM

  1. #1
    Lifetime Member DURAtotheMAX's Avatar
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    Default 2015.5+ Allison TCM

    I mentioned it briefly in another thread, but I figured I would start a new thread devoted to the new 2015.5+ TCM just to give everyone a heads up the details.

    Mid-year 2015, roughly after August 2014 build date, GM/Allison made some changes to the transmission wiring harness, changed to a new TCM, and new speed sensors.

    The speed sensors changed from the traditional AC 'analog' variable-reluctance type (IE, the type that has been around for 30 years) to newer DC hall-effect sensors that produce digital (square wave) signals. DC/hall-effect sensors are more accurate, less susceptible to signal noise/interference.

    And from an electrical/technical standpoint, its also possible with DC sensors for the TCM's to run more advanced diagnostics on the circuit and sensor...which gives more precise information to the scan tool when there is a fault, thus making it easier for technicians to diagnose problems.

    If you have a 2015 truck, look at your glovebox RPO sticker... if you see the code "AVF", that means your truck is a late-build 2015, and has the new DC speed sensors and new TCM.

    The TCM on 2015.5+ trucks with "AVF" RPO code is completely different. The 2015.5/AVF trucks no longer use an Allison A40/A50/T14 controller. They now use the GM T87 controller. It looks completely different, has a different connector, and is made by Hitachi. Its the same TCM that the 8-speed 8L90 in the new Corvette and 6.2 half ton Silverados has.

    So now the Corvette (w/ 8-speed auto), 2015+ half ton silverado (w/ 8-speed auto), and 2015.5+ Silverado HD (w/ Allison and AVF code) all share the same new T87 controller. Note: the T87 is NOT the same controller that the Aisin 8-speed in the new CTS uses, the T87 is Hitachi and supposedly runs all GM-in-house software.

    The T87 is on parts restriction from GM (p/n 24272004)[SIZE=4px][/SIZE], but Im sure at some point Ross will get his hands on one to let 8-speed 'Vette and 2015.5+ Allison guys play around.

    Ben
    2005 Silverado, CC/SB, 4x4, LT, LILLY/Allison
    12.9s @ 108 mph

    many thanks to Ross and Paul

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    Lifetime Member DURAtotheMAX's Avatar
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    Default

    Heres a picture of it if anyone is interested.

    Click image for larger version. 

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    2005 Silverado, CC/SB, 4x4, LT, LILLY/Allison
    12.9s @ 108 mph

    many thanks to Ross and Paul

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    Lifetime Member GMPX's Avatar
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    Here is another picture



    We were lucky enough that one of our customers had an in house project on these and needed read/flash support ASAP, so we had a T87 TCM here for a few days to get that working.
    Yes you are right, they cannot be ordered yet so we are very thankful we had the opportunity we did.

    I have not even looked at the mapping side of them but I am concerned for sure as these run either the Allison or 8 speed ! Must be pretty universal in how it works which might mean nothing is carry over from the A50 or the T43. I think it was actually made by Continental, not Hitachi.
    But this appears to be GM's new direction, outsource the hardware design and keep the software in house (yay!!)

    Cheers,
    Ross
    Last edited by GMPX; January 8th, 2015 at 09:15 AM.
    I no longer monitor the forum, please either post your question or create a support ticket.

  4. #4
    Lifetime Member GMC-2002-Dmax's Avatar
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    Always something cooking in that back room at EFI-Live
    www.mscservices.net


    Tuner of many, many Duramax and Cummins Diesels.


  5. #5
    Lifetime Member GMPX's Avatar
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    Yep, always got a million things on the go at once
    I no longer monitor the forum, please either post your question or create a support ticket.

  6. #6
    Lifetime Member Dmaxink's Avatar
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    Quote Originally Posted by GMPX View Post
    Here is another picture



    We were lucky enough that one of our customers had an in house project on these and needed read/flash support ASAP, so we had a T87 TCM here for a few days to get that working.
    Yes you are right, they cannot be ordered yet so we are very thankful we had the opportunity we did.

    I have not even looked at the mapping side of them but I am concerned for sure as these run either the Allison or 8 speed ! Must be pretty universal in how it works which might mean nothing is carry over from the A50 or the T43. I think it was actually made by Continental, not Hitachi.
    But this appears to be GM's new direction, outsource the hardware design and keep the software in house (yay!!)

    Cheers,
    Ross
    Impressive... i need some of the coffee your on!
    -Kory

    I'm out of ideas? Nah trick... When in doubt, 0xFFFF it out!

    http://www.PPEI.com/

  7. #7
    Lifetime Member DURAtotheMAX's Avatar
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    Quote Originally Posted by GMPX View Post
    Here is another picture



    We were lucky enough that one of our customers had an in house project on these and needed read/flash support ASAP, so we had a T87 TCM here for a few days to get that working.
    Yes you are right, they cannot be ordered yet so we are very thankful we had the opportunity we did.

    I have not even looked at the mapping side of them but I am concerned for sure as these run either the Allison or 8 speed ! Must be pretty universal in how it works which might mean nothing is carry over from the A50 or the T43. I think it was actually made by Continental, not Hitachi.
    But this appears to be GM's new direction, outsource the hardware design and keep the software in house (yay!!)

    Cheers,
    Ross
    Wow!! Great work Ross!!! 4mb flash is impressive. Nice to see that GM is doing the software themselves instead of just tuning someone elses.
    2005 Silverado, CC/SB, 4x4, LT, LILLY/Allison
    12.9s @ 108 mph

    many thanks to Ross and Paul

  8. #8
    Lifetime Member Chavez91's Avatar
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    Got some T87 DMax files, if you need some Ross :P
    Josh

    '04 GMC LLY
    - L5P, Motech, 6-Spd Conv. ML Trans.
    '05 GMC LLY - 250%, 12mm, 67mm Custom Turbo, 6-Spd Conv. ML Trans
    '19 3500 RAM - Tuned Aisin 0_o

  9. #9
    Lifetime Member GMPX's Avatar
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    I did get a read from one sent in thanks. Really odd situation, looks like Allison are running their own code on the T87, it is not shared with the new 8 speed at all, just common hardware.
    The Allison read we got was OS 24274899, if you have anything different then please Email it to support.

    Thanks,
    Ross
    I no longer monitor the forum, please either post your question or create a support ticket.

  10. #10
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    Do you think the E67 can talk to this transmission?

    Thanks
    "All that is needed for the triumph of evil is that good men do nothing..."

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