You may not think you need a temp gauge for the transmission, but I can tell you if I had one I would not have fried mine. I know I had heat build up before it let go but I had no way of knowing. Now I have a probe in the rear end, transmission, boost and pyro. I starting to believe one is needed for monitoring every device with oil and moving parts. Those units are not cheap and need looking after.
MHO.
. . Preston. .