TRANSMISSION Solenoid Characterization Data Codes (8L90E)

[Highlex]

Finished putting a 2018 LT4 into a 1970 Camaro with a 8 speed (8L90E)

Engine harness, ecu, tcm was purchased from PSI conversions. Transmission is from a 2016 silverado that is converted from 4wd to 2wd.

Finished the swap and drove the car, drives decent, all 8 gears work, but the transmission shifts clunky and seems very confused. Sometimes it gets stuck in gear or slips into neutral. Bang Shifts too.

The only codes we are have all the p27 codes.

P27A7, P27AA, P27AB, P27AC, P27AD

No other codes. I suspect these codes are related to the TUN / PUN number not being calibrated into the TCM, so I had the ECM and TCM sent back to PSI for them to program the TUN number into the TCM and they said they did it and mailed it back. However when I got the ECU back these codes are still here.

What are my options now? I spoke to the tuner at PSI and he said he entered the TUN number... I have no reason to not trust them.

I cannot do a fast learn on the transmission because codes are present. I cannot tune the ecm with HP tuners because its locked, and having them unlock it will probably remove the TUN programming info that PSI entered into the TCM, in which case it would have to go back to PSI for that to be entered again. (2 week delay)

GM dealership cannot program TUN number into the TCM because the vins do not match or the vehicle doesn't have a body control module which MDI2 needs to see to verify some programming information.

Any tips? What can I do to rectify these codes?

[Highlex]

Would swapping in an early (2016) t87 tcm from a 2016 silverado be a smart thing to try because that would match the transmission better? Trans is a 2016 silverado 8 speed.