Synthetic ATF?

In the dually, I roughly follow their 50,000 mile change, so the 2nd change is coming up. I may do it a little earlier because a few of years ago, I went to a race in Penn. Never been there before and took a route that almost had my truck overheat from going up a BIG hill. Water temp was way over on the right. There was even a sign that said "No trailers over 26' (or 28')" but I thought I'd be ok. Luckily I crested the top just as I planned on stopping. A friend with a 1 ton Ford van, maybe diesel, with a smaller load, had to stop and cool off. But everything has been working fine. I have Amsoil in the engine too.

The race car trans fluid gets changed every year or two. But I don't race every weekend. Maybe 10-15 weekends. Trans get taken out every 4-5 years for JW to check out. - Footbrake, 5,000+ flash and 3,550+ lbs. I have a little cooler in front of the radiator to help.
Super Shift should do very well in trans-brake applications because that builds up heat real quick!