To those who have a Scan Gauge II, I think I have figured the X-Gauge code to display the transmission fluid temperature. It took quite a bit of research; Scan Gauge's website code did not work accurately/properly. I did some beta testing today, and it looks good. I'd like others to try the code and report back their results.
The picture shows the car in the off position, completely cooled, and not started in a couple of days. You will note there is a slight variation in the air intake temperature, water temperature, and transmission fluid temperature. I believe these figures are accurate and the differences are immaterial in nature.