Not sure what you would need to change without a problem being described. The transmission control is electronic and most of the problems that are non-mechanical would be solved by replacing the Shift Solenoid. I did a step by step video on my solenoid replacement and posted it on youtube
https://youtu.be/yOABDeJQrAE
I have no advertisement or sale/spam of any kind on any of my videos.
Hope it helps