Consider synthetic transmission fluid also!

Heat is the #1 source of problems for an automatic trans. Synthetics hold up much better against heat and potential breakdown.

Amsoil Universal trans fluid.

I've been using their Universal trans fluid in my 2004 Dodge diesel dually that I tow my race car trailer with and their SuperShift in my race car 904. My trans builder said to keep using whatever I have because it protects very well.
Car is race-only, but converter flashes between 5000 and 5400 footbraking, depending on weather and other factors, weighing 3,540+ lbs. Summertime hot-lapping in the late rounds is what concerns me the most and I have an external cooler also, but bypassing the radiator.