Great info guys, thanks! Yeah you see a lot of stuff that makes you shake your head out there on the road. Good to know on the tires and the speed, I did not know that. Thank you!
The Armada does not seem that big (my neighbor has one) as some SUV's and trucks. We don't like big vehicles so our Durango is the perfect size and the Hemi has the cylinder deactivation and I can get 22mpg on the freeway (not towing), about 14 around town. I know I am going to be giving some of this up but I really don't like some other vehicles out there, I know the Armada is showing its age a bit now so its a toss up. I am not a truck guy so the Armada is the next biggest vehicle w/out going to an Expedition or something like that but going bigger than the Durango. Its a third vehicle for us, we don't drive it daily so its not the end of the world on the mpg I guess. They seem to ride super smooth, impressed with that.
Those mentioning shifting, I put mine in 4th toward inclines and just keep the rpm in the 3500-4000 range as that is where max torque is and it was content there on the inclines. I had heard leaving a vehicle in drive can cause the torque converter to slip and the transmission to heat up as it hunts for gears on hills. Im no expert, just what some have said but it seems to work. Thanks again for all the info.