In 1972 i had a 4 wd 3/4 ton Chevy suburban, and we bought a new 31’ Holiday Rambler travel trailer.
We made several 4 to 6 week trips west with it all thru both the US and Canada Rockies.
Down shifting on grades with the auto trans was just a natural thing for me to do.
I once had a trailer brake issue on the road while in Maine, and we lived in PA.
I just unplugged the trailer and drove it home by using my head on speed, keeping my distance from others, and using the trans and truck brakes.
Drove the Chevy over 200.000 before i traded it with no tranny issues.
I did have a large tranny cooler on it however strapped on front of the radiator.
Back then they used a clutch fan system, where the fan didnt engage till the engine temp called for it.
But i had mine set up so the fan ran all the time, and that helped alot on those long steep hills.
My current Chevy truck is a 2016 and that tranny will downshift on its own on grades.
But i still at times do it manually.
