the truck has a variable vain turbo (excuse my spelling if its wrong). down shifting manually and when the truck does it on its own are very different. if you downshift, it is strictly the engine slowing the truck, but if it is in tow haul, the turbo will create back pressure which will be like an engine brake on steroids. may be hard to notice at times but if you try both while going on a slight decline, you will notice a pretty big difference.
also, if you have a lead foot, you will likely never notice a difference in the shift points. take the truck out in tow/haul and get it up to 60-65mph. then turn the tow/haul off, you will notice that the truck wont go into 6th gear while tow/haul is on until you get to a pretty high speed (70+)
hope i helped
also, if you have a lead foot, you will likely never notice a difference in the shift points. take the truck out in tow/haul and get it up to 60-65mph. then turn the tow/haul off, you will notice that the truck wont go into 6th gear while tow/haul is on until you get to a pretty high speed (70+)
hope i helped