MDKMDK, Yeah I neglected to mention the GM dealer I worked with recently wasn't any help as the only "GM" solution is to enable the trans temp function in the information screen. Unfortunately, our particular configuration omitted this feature. I asked them to program it in but, they explained they could, or would, not do it as all they can do is reprogram existing functionality. They actually did this when they replaced the body control module and the instrument cluster... both of which we paid for! And even at that, they would not install the trans temp feature.
The nearest GM dealer that will work on a RV is 105mi from us.
Gary