2009 Colorado Factory 5.3L (LH8) to 6.2L (L92) Conversion, Info Gather

[OEMOBDII]

OK, I picked up a 2012 6L80e 4x4 transmission for $650. My Colorado is a 2009. From nearly everything I have read, it seems there was a change in 2010/11 in which the newer T42's are not reflashable back to an older OS? This case would he 2012 going to 2009. Is this just with HPT, or even with GM tools such as Tech II and MDI (I do have unlimited access to these and the GM database subscription).

If the T43 inside the 6L80e can not be back-dated to 2009, then I think I have 2 choices: (1) change out the T43 inside the 6L80e with one from 2009, or (2) change out my E67 to or forward flash it to a 2012 OS? Please check my thinking on this. I apologize this question is not even portrayed in the thread title.

Once the E67 and T43 OS years are matched by either method above, do any changes need to be made inside my E67 for the 6L80e to work?

Thanks again. All ears, and taking notes.....

[IARLLC]

I vote for a 2009 PCM and TCM. The TCM is of course flashable but it might cross a line around 2010...so a 2009 TCM will be the simplest way to get up and running.

Regarding moving up to a 2012 PCM...While I think 2010 PCM/TCM might have some minor improvements I would be concerned about BCM, EBCM (ABS), and TCCM (transfer case) control issues. No airbags, service vehicle soon lights, ABS flashing... not everybody wants that on their morning drive

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I'm aware it's an older thread, but ​what was the outcome from this? I'm looking at the LS3 to swap in to a 2.9 AR5 rwd equipped truck. I'll use the trans adapter for retaining the AR5. Just not sure where to pluck the harness & PCM from to retain a "like" oem operating truck. Mechanically, I have solutions for the swap, just not 100% with the electrical/electronics.