Since I have an e-fan in place of the clutch fan, I have been able to do some experiments... When the engine reaches 200 deg, if it continues to climb, the AC fan will turn on even if the AC is off.
Since the AC fan is right behind the trans cooler, I would assume it will turn on if the trans temp starts to climb? My trans has only ever gotten to what I would call a high temp once, when I was driving it very spirited
I'll activate the trans gauge on my BD and see if I notice the AC fan being related to trans temp as I drive over the next few weeks.