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Thread: A50/T14 confusion

  1. #41
    Lifetime Member DURAtotheMAX's Avatar
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    Quote Originally Posted by vectorbundle View Post
    A41 is not for GM pickups or MD trucks, forget it.

    T14A (GM serv #24256864 on sticker, part #24256671 and T14A on the case) is Delco branded version of Allison A46 (part # 29546675 and ATA4601 on case). they are the same hardware.

    T14 (GM serv #24256861 on sticker, part #24256670 and T14 on case) is Delco version of Allison A50 (serv #25978353, part #29545535).

    T14 is to A50 what T14A is to A40 -- sort of. there are some differences that are part of the boot level. SPS does not write to that, it only writes the OS and trans cal segments.

    when you flash an 06-08 GM pickup with SPS you must select the TCM type (list of part/service #s that just determine if it's T14A/A46 HW or A40). the cal segment for 08 will be the same 24257976. the OS will be different 29541751 (A40), 24256580 (A46). cross flashing will brick. you will find similar pattern when selecting A50 vs T14 for 09-10 pickup -- same trans cal, different OS.

    you cannot SPS an A50 selection into a T14, it will brick. generally you cannot flash a file you read out of an A50 with EFIlive into a T14, it will brick. just as flashing A40 OS and cal into an A46 will brick. in some cases i can recover them.

    for some strange reason for 2011+ GM pickups the same GM flash works in A50 and T14 (at least that used to be case, they may have made some "improvements"). i haven't figured out yet why that is, i don't have any A50s left to test stuff on and generally have no reason to use them.

    there are a couple of problems specific to SPS and MD trucks. GM never updated their MD Allison A40 and A50 software for T14A and T14. there IS no MD calibration in SPS for the new controllers. and there is no TCM hardware selection screen. so people install a new T14A in their 08 MD trucks figuring GM says it's a replacement for an A40 and flash it for an 08 MD VIN... brick. SPS a T14 in 09 MD truck... brick.

    what's worse, SPS also bricks an A50 when flashing for an 09 MD truck (that's an error with SPS, it's not a problem with the controller). A40s flash OK for 06-08 MD VINs. but as far as EFIlive is concerned, as long as one flashes only what was read out of a TCM with the same HW, there is no problem. there is no fundamental flaw in the T14 or T14A TCMs. the fundamental flaw is GM's support and documentation.
    Awesome tech info, thanks!!

    So people with 06-09 MD trucks are just SOL if they need a new TCM? Their only option is to find a used A40 for 06-08?? And nothing for 09? Or just put a used A40 into an 09 MD if you need replacement?

    And you said A50 will brick when flashing for an 09 MD? Did the 09 MD's come with an A40 or A50 from the factory? So if they came with A50's from the factory, you're saying there is "NO" reflash at all for any 09 MD's?

    Does the A50/T14 not have J1850/Class2 comms capability?

    On another note....do you have any ideas why its "somewhat common" for 2011's to eat TCM's?

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

    many thanks to Ross and Paul

  2. #42
    Lifetime Member DURAtotheMAX's Avatar
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    When they brick, do they fully go brain dead and not even boot? Or just wont be recognized by SPS/dealer-level software?

    Can they be recovered by Allison software, or "other" GM software?
    2005 Silverado, CC/SB, 4x4, LT, LILLY/Allison
    12.9s @ 108 mph

    many thanks to Ross and Paul

  3. #43
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    A50 has no J1850 capabilities afaik. a takeout A40 (with appropriate programming) will work, people used to swap them over to tune before A50 support was available. for a *new* TCM, afaik MD guys are SOL with SPS. they are probably SOL with a typical Allison dealer too because their system has no GM cals anymore.

    i have ways to set up the new controllers for MD guys, the point is it can't be done with SPS. these TCMs can be "converted" but that's not exactly an off-the-shelf OEM process for a typical guy out there with a bad TCM.

    what i described is not necessarily an exhaustive or up to date state of affairs with SPS. i don't use it anymore. there were also cases when SPS bricked TCMs for no discernible reason whatsoever even with correct TCM HW selected. if you are not careful and flash the wrong TCM -- definitely brick, so at least don't do that. correct TCM -- eh, maybe still brick. the system sucks (not the TCM). recovery is impossible more often than not.

    i agree that 2011 TCMs *seem* to fail disproportionately. i don't know why.
    Last edited by vectorbundle; June 1st, 2017 at 03:06 AM.

  4. #44
    Lifetime Member DURAtotheMAX's Avatar
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    Quote Originally Posted by vectorbundle View Post
    A50 has no J1850 capabilities afaik..
    Ah yeah, makes sense...since the GMT-560's still use Class 2 for the instrument cluster and body stuff.
    2005 Silverado, CC/SB, 4x4, LT, LILLY/Allison
    12.9s @ 108 mph

    many thanks to Ross and Paul

  5. #45
    Lifetime Member comnrailpwr's Avatar
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    This has struck me again. Customer brought me a 2009 with an acting up A50 TCM. the replacement that dealer gave him was T14. I read out his Factory A50 TCM as he had transmission tuning. Are then installed the T14 and read that tune out as well. It had some data in it but looked a lot different compared to the regular truck data. I then flashed his original A50 file into the T14 replacement. That's generally what I always do. If flashed in without any issues but it had a traction control light on and was shifting hard into gear. I then made all the changes to the T14 file I read out of the new TCM to match what his A50 TCM originally had. That file will not Flash and errors out $0101. Both tcm's do auto-detect as A50. I'm not sure what to do with this problem without tis. I now do have a tech2 but have yet to use it.

  6. #46
    Forum tyhee Site Admin GMPX's Avatar
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    Does the T14 read as an A50? Are you able to post up the T14 file that was read out if that is the case.

    The user 'vectorbundle' said above....
    "You cannot SPS an A50 selection into a T14, it will brick. generally you cannot flash a file you read out of an A50 with EFIlive into a T14, it will brick."

    Given that, I don't know what you are supposed to do with your T14's.
    Need official EFILive help, please go here.
    For tuning support please post your questions on this forum (or other auto forums).
    Sorry if I don't respond to your PM, don't take it personal.


  7. #47
    Lifetime Member comnrailpwr's Avatar
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    Yes it auto detected, read out and saved as an A50. I see his remarks now after I came back to this thread. For some reason I un followed it and stopped getting notifications unfortunately. Having trouble attaching file via my phone and external drive. I'll email it to you.

  8. #48
    Lifetime Member Chuck CoW's Avatar
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    Default I'm generally VERY careful with later TCMs.....

    Quote Originally Posted by GMPX View Post
    Does the T14 read as an A50? Are you able to post up the T14 file that was read out if that is the case.

    The user 'vectorbundle' said above....
    "You cannot SPS an A50 selection into a T14, it will brick. generally you cannot flash a file you read out of an A50 with EFIlive into a T14, it will brick."

    Given that, I don't know what you are supposed to do with your T14's.
    I'm generally VERY careful with later TCMs..... When TIS flashing TCMs, (especially in Duramax trucks) many times the

    software asks for a TCM PART NUMBER.... and the list usually has 20+ choices.... Don't want to own that one!

    Have the replacement flashed by someone with TIS and then start with the latest calibration that was read from the

    controller to avoid problems.

    Chuck CoW
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