Well when I bought my Lightning it already had a Trans temp gauge in it. But my question is simple...what is the normal range of operating temperature?
mine gets real close to 180 if i leave o/d off and drive at low speeds for an hour. never went above 170 before i messed with the shift points. right now it never goes past 180.
For normal city driving ... it depends on your convertor. A higher stall (aftermarket) convertor will get a bit hotter around town. My stock would operate around 160-180 and with my PI 2600....it gets to about 190 or so.