This is an interesting thread. My 07gt will always shift aggressively the day after it was driven hard and granny shift a day after sitting in stop-n-go traffic for my 2 hr commute. If driven hard multiple days in a row it will continue to act accordingly. I just assumed this was normal, given it will learn the drivers style, and didn't think much of it. Does the hall effect sensor suffer from metallic debris accumulating on it or the associated reluctor, or does the magnet weaken over time? I didn't take the time to read any of the links in this thread yet, but it looks like you found a happy solution for you without tearing into the trans.