americanrascal wrote:
Does the 5500 RPM bother you all or should I be shooting for a lower RPM (???) with a bit of brakes, no manual downshift, - cruise set to off and in tow haul. 
Thanks for the good advice here ! I do appreciate it. 
Rascal Joe
That's high RPM, but it won't hurt it. In tow/haul when you push the brake on downhills it downshifts, so you can't really pump the brakes down a hill, or you will experience what you did. Kinda freaked me out the first time as well. I think on down hills it's better to shift to manual mode and do like the semis do and try to choose a gear at the top of the hill that will keep you at a safe speed without braking too much. Some braking may be necessary, but then it won't downshift and rev up like that unless you do it manually. 
Hope that helps. I love my truck, and the 6.2! I've only got 4K miles on mine, but I still get a big grin every time I get in and drive it. Not being a daily driver, I don't care about the mileage. Tows our TT very well.