My 2007 CTS 3.6 is not shifting correctly into 2nd gear, flair/ long shift or normal it's like a woman deciding what she wants to have for dinner, you don't know what's next. My Tech2 shows 0 shift time, although it will show a correction time varying around .50. Does anyone know what the transmission uses to detect when it has "shifted"? Watching shift data in the only thing I notice that looks funny is the 0 shift time no matter if was a long shift, a flair or a firm fast shift. Only for 1-2, other shifts have a shift time.
History: I did adjustments to the sport mode to firm up the shifts and almost always drive in sport mode. It would chirp 2nd, wot, on the right road surface. If my wife drove, it would shift normally. I have reverted back to factory programing for diagnostic. I thought I had broke something so I pulled the pan. The pan was quite clean for 175k miles, no glitter in the oil and and surprisingly little clutch material. I changed the filter and and I'm getting back to diagnosing. Any thoughts?