Problems Adding Crate 6L80

Hey folks new to the forum, just looking for help. (HP Tunning pool is kind of shallow here on AK)

8-10 years ago, completed a Gen IV 5.3/6L80 swap from a 2010 Silverado to a 1993 Toyota Land Cruiser

Many years of great fun & offroad adventures

However this fall soaked the 6L80, could not find a rebuilder I was confident off, so elected to bolt in a crate 6L80. Bypassed the entire harness, plugged directly into the tranny TCM, and flashed the factory program.

Now it goes into ?forward ? at every position R-N-D accept Park. (Never had limp mode during this process, 3rd&R) Is an HP Tuner technician necessary to complete the programming, or do I have another problem ?

Are you saying you flashed the crate 6L80 with what you read out of the 10 Silverado 6L80 TCM? There are 4 different part # TCMs used from 07-18 and maybe newer. 10 and 11s used 24275874. You need to find out what TCM is in the crate 6L80. It may not be compatible with calibrations used in the 10-11 TCMs.

Can the TCM self identify?
(Not sure GM?s rebuilders know what parts they are using )

Not hardware wise that I'm aware of. Did you happen to read the TCM before you flashed it. Knowing the segment numbers that were in it might give a clue to what year TCM it is. My experience with new out of the box AC Delco TCMS are that most if not all are remans that have some program in them. Here is what I was given by my GM parts guy for the different ones used over the years. It has been a while since he gave me those part numbers and the last one may continue past 2018. Also GM is bad about changing part numbers so they may still be good or maybe been superseded. I have never had much luck putting a different year program in a TCM not for that year.

07 - 24275871
08-09 - 24275872
10-11 - 24275874
12-18 - 24275873