I tow fairly heavy alot, grossing 24,000 to 33,000. I will get anywhere from 7 to 11 out of my dodge. It usually stays around the 9 or better but on the curvy hilly backroads around here you are working it all the time on and off the throttle.

 

I pulled this from Seattle,WA to Columbia,SC and I averaged about 9-11 mpg depending on what part of the country I was in. Out there through Idaho, Montana, and Wyoming it was around the 9 range. Once I got out of those mountain passes and the continental divide and got into souther Wyomin and western Nebraska, from there on in to Columbia I did much better. Your rear gear is gonna come in to play here too. I've got what I think is a 4:10 with 35" tires. I'll run about 70/75 at 2K rpm.

 

I'm thinking you might have 3.54 running 2k at 70-75. I run around 2k @ 65 with 4.10's. But you do have taller tires maybe your right. I don't know

 

I've got 3:73 in my 05 6 speed and when i'm cruising at 70-75 i'm running about 2200-2300 i do have 285's on 20's though

 

i pull a 52' car hauler with three trucks cars etc from utah to cali all week long and get 12-13 in my 94. all stock just straight 4 inch exhaust straight piped

 

NO i did not but i am looking into a newer intake system

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Well the yamaha rhino wieghs about 1500 pounds then the bruteforce wieghs another 750 or so and same thing for the polaris sportsman is about 650 and then the trailer weights around 4500lbs maybe less i dunno its a dual axle trailer with 7k lb axles my truck dry wieght is 7200 its a full size cew cab 6.0 loong bed so im not really to far off when i say total wieght fuel gear guys quads trailer is about 12k thats the complete rig not just the trailer and quads

 

when hauling hay 30k+ I get 6-7mpg out of mine@ 65-70mph on the highway, but thats with a tall load in the wind

 

I have a 2005 Dodge DRW 4x4 3.73 gear and G-56 6speed pulling a 53' Take Three trailer hauler loaded anyware from 25000-35000lbs gross and average an IFTA quarterly 11.1 MPG, the lowest i've ever got towing was 8MPG and that was 34980lbs,bad head wind, and height of 13'8" up over the bed. Your not alone with your 6.4, I know of 2 trucks here in Michigan that the owners ended up suing Ford and getting them bought back under the lemon law,( more than just bad fuel milage)

 

about twice a year i pull a goosneck with a 12,000lb kubota mini excavator and a caterillar 272c skidsteer with atachments and get about 13-14 driving were we are at

 

i get bout 12 to 14 with loads of hay on between 35,000 and 54,000 gross