On my 2014 SRW Longhorn Limited with Aisin and 3.42's, I tow in 5th to keep the RPM's up to 1750 (about 66 MPH). I start out in Drive and, as I reach highway speeds, shift into 5th. Most times the dash display indicates the transmission is in 5th or 6th when I make the switch but on occasion it will indicate the transmission is still in 4th. In that case, I just shift up to 5th. Pretty cool to be able to see which gear the transmission is in while manually shifting! Traveling empty I just let the transmission do it's thing although I always use the EB and frequently use TH when slowing down. The dealer told me during our short orientation that the EB in the full on position helps the truck keep the catalytic system clean by being partially on all of the time - have no idea if that is true or not.