I had a 2007 2500 5.7 4 door short bed truck that I bought new. I forget which rear end ratio the truck had, but I know it wasn't 4.10s as my dad has a 05 reg cab long bed with 4.10s and he gets 10 mpg towing or not. I would get 14-15 mpg not towing and then about 7 mpg towing a 24' box trailer that is right around 8K loaded. I do have 3 decent size hills on my way to the race track that kills the mpg. I traded my 070 in on a new 2017 2500 6.4 crew cab, short bed with 4.10s. My truck has the 6 speed, not the newer 8 speed trans. Also, the new trucks no longer have rear leaf springs. Doing the same type of driving the 17 gets the same mpg empty and just a tad better towing. It has WAY more power, stops better, drives nice, ton of room inside. I don't like that it's sits higher from factory as it makes it hard to get stuff in and out of the bed of the truck. Mine also came with a 2 1/2" hitch receiver so you have to use an adapter for your 2" receivers or buy a 2 1/2" receiver. I only have 24K miles on the truck so it doesn't get driven much, but it's nice to drive when I get it out.