I have a 2007 model scangauge and it doesn't have trans temp on it. I know that you can program in other things that the computer reads and have them displayed.. I actually have horsepower readout on mine. It seems to be pretty accurate. My truck makes around 270whp and it shows that.
I'm gonna send them an email and see if I can program in the trans temp readout. Would really help when towing!
The scanguage 2 is capable of reading trans temps, but they dont have the codes for our trucks (or something along those lines). I remember emailing them asking about the upgrade (i have the scangauge 2 before the x-guage firmware) and they told me that trans temps didnt work for our trucks. Maybe it has changed though, havent emailed them lately.