Originally Posted by
Taz
OK ... in post #1 you used the word "customer" - which implies you run a business of some sort. Standard operating procedure as a reputable tuner is to confirm what has been done / changed / installed by the owner or another shop prior to the vehicle being brought to you.
In this case, obtain 2007 T42 pinouts for both a 4L60/65/70 and a 4L80. Then confirm where each pin in the main transmission connector, VSS connector, and ISS connector are routed to, with respect to the TCM connector. Once you determine if there is, or is not, an issue with the wiring, then move on to the calibrations.
My two cents is to always start fresh with respect to the calibrations. I would flash the ECM and TCM back to their OEM stock calibrations, and then tune from this point. Obviously this would put a 4L60/65 tune back in the TCM - but that is OK (actually necessary) to establish appropriate communications with the ECM / IPC, etc.
If you go this route, post the tunes (something you omitted to do thus far), and I will help you morph the 4L60 tune into a 4L80 tune, if that is what you require.