I would certainly use the tow/haul…can’t hurt
does the trailer have brakes and do you have a controller? That’d make your trip over teton pass a lot less errr….exciting.
Regardless, use your gears. I have a manual trans so can’t really tell you exactly how the t/h will effect your trans but I’d guess that it in part will lock the T/C so you will be able to better gear down. If you’re riding your brakes to keep from going too fast then you definitely need a lower gear. Even lightly riding the brakes will heat them up (hard on them if nothing else but possibly leading to glazed/warped rotors, premature pad failure and ultimately total braking failure). It’ll take a bit of self discipline to roll down some of the easy straightaways abnormally slowly with the gears but you’ll be glad of it when you come to a curve.
And just for me, cause I hate an autotrans hunting around on the uphill, I’d use the gears going up as well.
oooops, just noticed that's tejon pass, not teton pass. I have no idea how steep/windy tejon pass is but assume that it's less daunting than teton pass
. But most of time driving home takes a tank and 1/8 of a tank. I'll post my mpg when I get back home...hopefully I don't hit any crosswinds.