T43 2007-2009 OS Reflash Compatibility Question

Hi all. Great site, first off thank you for all of your input, it really creates an amazing knowledgebase with enormous benefits. I am anxious to contribute once I learn myself.

I am updating my initial question from 2 years ago, as the situation on my side has slightly changed yet now finally going forward. I have a factory stock 2009 Colorado V8 (E67 ECM), and wish to swap the 4L60 trans (T42 TCM) to a 6L80 (T43 TCM). Several have done it successfully. I have read a bunch here, and it looks as if it works best to match the ECM and TCM operating system years, 2009 in my case. I picked up a complete 2007 4x4 6L80e for $500, so my first question will be can my 2007 T43 be updated to 2009 operating system? I do have full access to GM MDI subscription/system, and would "bench" flash the T43 via the MDI and appropriate connectors, (maybe have to use CAN bus termination resistor?).

It looks like the T43 changed dramatically in 2010 (except Camaro), and that year line can't be crossed, understood. So my question resides around if my 2007 T43 can be updated to a 2009 OS?

Final question would be what needs to be done to "marry" the E67 to the T43 so they will communicate? I have read of this several times. Not sure if there will be issues of the T43 having a different VIN residing in it (when reflashing with GM MDI or otherwise).

Thanks again.

Hi.

EFILive won't let you go from 2007 to 2009 on the T43, TIS probably will but I don't know if that is going to cause issues. The changes GM made to the 2010+ T43 were done to ensure there was no way the older OS's could be flashed it, obviously there was some changes that they couldn't risk going in to the older TCM's.
Nothing really needs to be done to marry the two modules, you could change the VIN just so they are the same for consistency but as long as the ECM and TCM programs are from the same vehicle type then they should happily talk.