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Thread: 2006 GTO e40 to T42 tcm will not pickup speedo

  1. #1
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    2006 GTO e40 to T42 tcm will not pickup speedo

    Any help at all is greatly appreciated. E40 ecm hooked to t42 tcm in swap. Can't get it to pickup speedo no matter what I do. I can go into vcm scanner and see output rpm on transmission side. I'm at my wits end. Changed everything I can possibly think of. 2006 gto engine, 4L80e trans, BP harness and T42 tcmzollo4.hpt

  2. #2
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    The 2008 Express TCM OS you are using (24239927) doesn't work with any E40 OS I know of. And I have not seen any non-GTO TCM that works with the GTO OS. If I were you I'd go back to a GTO 4L60E TCM and use a 80E conversion (relay) harness.

  3. #3
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    thank you!

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  5. #5
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    Is it possible to write a different OS to E40 that would be compatable to 24239927? Or would it be a truck file only?
    Just grasping at straws

  6. #6
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    The 2008 Express TCM OS you are using (24239927) doesn't work with any E40 OS I know of.
    Not GTO, not Trailblazer, not SSR, not '05 Corvette, nothing. 24239927 does work with early E38s in pickup trucks, that's what is being talked about when that TCM is mentioned as a solution to 80E swaps.

    If you change the ECM over to '06 Trailblazer you can use the '07 Suburban 2500 4L80E TCM (24235341, same TCM OS ID as what the Trailblazer 4L60E used), but in non-swaps there are quirks - I believe everything works except comms to the IPC for the gear indicator? It's still not perfect, I don't know what if anything you would run into in a swap without all the other factory stuff. If you want to KNOW that everything is able to work as it should be, it's GTO ECM, GTO 60E TCM, and relay harness.

  7. #7
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    Also know that changing the ECM OS may leave you with throttle pedal & TB that no longer work.