Retired JSO wrote:
My 6.2 with 3:73 rear gear gets 7 1/2 mpg average pulling our 25’ toy hauler 65 mph. Toyhauler has a gas golf cart for a total weight of 8,558 lbs.
Toy haulers tend to be tall, wide and boxy. Horrible aerodynamics. I recently pulled a single axle box trailer about 500 miles with at least half of that empty and it couldn't have weighed much more than 1500lbs with the load in it. I was astonished at how hard it was to pull compared with a tandem axle flat bed that I use quite a bit or even a 3 horse trailer. It was like pulling a parachute. Weight is a factor around town and on hills but on the highway aerodynamics can be much more important.