i have a b&m trans temp gauge. i went to the strip and drag raced last night and my temp never moved off 100*.. i felt the lines on both the trans in the radiator as well as my cooler lines and they were pretty warm. should i move my sender to the tranny itself or is my gauge messed up? i have the sender inline on the top trans line of radiator...

 

Oil to the cooler is usually too hot. Oil from the cooler is too cool. The oil temperature that should be measured is what's in the pan. That gives you an indication as to how hot the oil is getting after the hydraulic circuits use it. To and from the cooler temperatures can fluctuate a lot very quickly. Measuring what's in the pan can also tell you how hot it is even after it's been sitting for a while. If the sender is in a cooler line, it will cool off quickly while the oil in the pan is actually still hot.

The transmission oil should be roughly the same temperature as the engine but can run much higher. After around 240*, bad things start to happen.

I don't even bother with tranny temp now. I just use a large cooler and a deep, finned pan and let them do their job. Even with a high stall converter and a transbrake, I know the temperature spikes but it also comes down quickly. If I go rounds and need to hot lap the car, then I know the tranny oil is getting a little hot.