Test port on 1992 4T60E transaxle

Ive been thinking of installing a transaxle temperature gauge because I tow with my Trans Sport van. Ive been reading that the best place to install the gauge is in the pressure test port. I have a factory service manual and it refers to the port but does not show the location. Does anyone know the location, and the thread size, of the port? Thanks, wagonman76

Actually, the best place for a temp guage is to install in the cooler line. Install in the output line. This is the line where the fluid exits the transmission and enters the cooler. This is where the fluid is the hottest. You want to know how hot the transmission gets at its hottest point.

transman