I'm looking at a 2001 F550 4x4 4 door. It has been converted to a truck bed. The problem for me is it has 580 gears. I'm wondering what kind of fuel mileage it will get pulling down the highway. Does anyone have a similar configuration?

What are you getting MPG
What RPM are you spinning at 65? On the test drive this truck was at about 2400 at 65.

Thanks for your input.

I dont think you can use mileage and 550 in the same sentence .

according to this its between 5 to 11mpg
http://www.fuelly.com/car/ford/f-550%20super%20duty

I hear ya... LOL

If I could get 12 I would be happy since all I'll be doing with it is pulling the boat. If it's down around 6 or 8 I don't think I would make the move.

Thanks, I was hoping to get some real world numbers from guys who have one.

buddys dad has one, cant remember the year, but I think he gets less than 10. towing a 11k horse trailer like 6 or 7

I had one with a 7.3 crew cab hauler body fuel milage was not good if you went over 65 honestly I don't remember how bad 6-8 . 10 if under 65 the bigger issue was over 70-75 the a/c would not keep up the cab and floor got to hot. sold it and bought an 06 550 big mistake milage was better cause it was on the back of a tow truck so often but I can say it was a great truck it has huge brakes and lots of pulling power . I priced changing gear ratios, keep buying diesel fuel its cheaper. I tow a cig café with trailer about 13-14000

If it is a concern you could always go to a 19'' taller tire or ever a 22.5 semi bud wheel and tires to drop the gear ratio...kinda like swinging a huge prop! ..

I have an '02 F550 4x4 crew cab with dually bed conversion and 4.88's. Has an AFE intake, 4" exhaust, Garrett GT38R ball bearing turbo, and DP tuners chip. It runs around 2400RPM at 65 mph, 2500RPM at 67-68 mph and realistically 70 is top speed on the highway. Gets around 12 mpg empty if you keep it at 65 or slower, 9.5 mpg towing 10k lbs in some smaller hills , 8 mpg towing 18-20k lbs on flat ground, and 7-7.5 towing 15k lbs in big hills out west. I've put over 200k miles on it mostly towing so that is real world first hand info.

i have a f650 with a 300 hp caterpillar with 430 gears. 245-70-19.5 tires 2300 rpm at 70 mph . 11mpg not towing . now with 255-70-22.5 tires 1800 rpm at 70 mph i have not yet checked the fuel miliage . just made the changes . it has a 6 speed allison auto . i'm hopeing for better mileage.