Has anyone changed their transmission fluid and would they recommend doing it or leaving the factory fluid?

Does anyone know what screw head type or tool type you need to remove the drain and fill screws for the front and rear diff fluid? Also is Maxima Gear Oil 80w90 acceptable for the diffs?

I recently flushed the radiator and put in prestone radiator flush solution with distilled water. It ran fine while I ran it with the distilled water and radiator flush but after I drained that and replaced it with prestone 50/50 it overheats very quickly just standing still from a cold start. Any idea what this could be?