I have a 2008 6.4 F-350 that came with the Tow Boss package (4.30 rear end). I pull a 39’ 5th wheel camper that weighs about 14,000 lbs loaded. I have noticed that when using the Tow/Haul mode and going down steeper grades (nothing drastic) that it will gear down to the point that my RPMs will run up to 3,500 to 4,000. I HATE the way this sounds and it makes me feel as if I am over revving my engine. When this happens, I usually turn off the Tow/Haul so that I can “manage” my RPMs with my brakes. I do not “ride” my brakes, rather I slow the truck down with my brakes and then gradually build speed and then slow down again. My question is this - are there those out there that just leave the Tow/Haul on regardless, even if it runs your RPMs up to 3,500+? I just don’t see how this could be good for an engine.