Im planing to buy a Transmission temp gauge and ive been reading wheres the best place to put the sensor and im wondering what you guys think. ive read on other forums that they put it in the pressure test port, pan, or inline with the transmission cooler lines with a T fitting but im thinking more on putting it in the pan

 

IMO your best reading will come from putting the sensor in the trans output line. That is what I did in my truck. You will see the fluid at its hottest there and that is what you should be reading with a trans temp gauge.