I believe theres a way to tune it where it wont shift out of first when its manually dropped into first.. but if you dont tow anything the tow/haul button is easy to setup for it.

 

200 miles on new 4l80 temps holding 150 in traffic will be towing travel trailer in a couple of weeks, can't wait, I was always afraid of trashing another tranny with 4l60. This swap could not have happened with out the excellent info on this site.