Hey I am planning on putting a temp gauge on my transmission and was wondering where is the best spot to put the gauge for accuracy. I've read people having them in a test port and also in the pan. I no the computer reads the fluid in the pan and if the pan is the best place to read temp, is there a electrical temp gauge I can get that i can wire to computer to read the sensor that's already there. It's a91 F-150 4.9l E40D

 

Just put it in the Test port. No drilling/welding/draining of the pan.
Pan gives a lower reading of what the rest of the fluid is also.
Don't try to tap into the computer. These transmissions are already temperamental with their electronics, we don't need anything else to add to it.

 

e4od test port

 

The pan temp will tell you what's going on in the transmission, and the test port I believe is just after the pump which picks up from the pan anyway.

Some people like to put the temperature probe in one of the cooler lines, usually the hot line leading up to the oil cooler, but all that does it show you max fluid temp after the torque converter (the hottest point in the system) and not necessarily what your transmission itself is running at.