GM LS3 Crate Engine With a 6L80

[sinistriel]

I'm wondering if anyone has run into the issues we are currently having. We are installing a GM Crate LS3 into a customers 67 Camaro, we are a transmission shop and have built a heavier duty 6L80 to go into the vehicle. The ECM from GMPP has the E67 with OS 1250244, we believe we are getting an OS software mismatch between the TCM and the ECU, we have a U100 communication code and are not seeing any VSS output in any scanner, trans sticks in limp mode. We originally started the car with a TCM meant for a 2010 Camaro/Corvette and flashed the TCM with the OS for a 2010 Camaro SS, we had limp mode, flashed with the OS from a 2010 Corvette and the car would no longer limp mode and had first gear, but would not shift out of first and no VSS. We read a few forum posts and found out the 6L80s that GM builds for the Supermatic Connect and Cruise version use a TCM out of 15+ trucks due to the VSS being wired and sent out through the harness. We tried an appropriate TCM off of a 15 truck and the correct OS for that year and still no VSS registered and an immediate U100 and limp condition. Has anyone tried this or have experience with a possible OS we could flash in the TCM if it is a mismatch issue we are experiencing?
Many Thanks

[CrazyCanadian]

GM plug and play connect and cruise stuff is a different animal...all though they use OEM ecu's they aren't the same as the production ones you find in cars. I would contact GM and talk to them about a connect and cruise TCU for the transmission.