I agree with JPD.

A truck that is tough enough to tow 15000 lbs (an F350 dually or better) is not a reasonable truck for any other purpose.

I tow 13000 lbs with a F350 dually V10, not diesel, because I (mostly) only tow with that beast, and its just not worth the extra $$ for a diesel truck: the payoff is about 100,000 miles. That's a lot of driving.

The shocks are so stiff that its like being mugged driving down the freeway when I'm not towing.

I have a car and a bicycle for when I'm not towing the boat.

There's another big payoff on the diesel- resale value and durability. If you pull alot and often, the gas engine just isn't going to hang in there the way the diesel will. Unless you're going to wear it out and dump it, a diesel engine will help the truck retain significantly more value. Plus, you got to have that big torque for those long hills the whole time you owned it. It's alot more than just fuel economy.

I have a 04 d3500 dodge dually mine is the 325-610 cummins I get 22.2 on the hiway 19.1 around town. It is fussy about fuel. around the chicago area we have custom fuels for pollution control, using those fuels it will drop in mileage to 20.6hiway and 17.0 around town. Mine is an automatic with 373 rears. I put a good convertor and deep trans pan on it, because the convertor is the weak link in all these factory trucks no matter what brand. I do run all synthetic fluids.

gotta watch those diesels........everythings great until something goes wrong, then their a zillion dollars to fix.......one fuel injector for a new Ford 6 litre diesel.....$600!!!......change all 8 plus labour.....7g's.......insane

that's not quite right..... I'll sell ya all the new-exchange 6.0 injectors you want for $276.27 each, they are in stock today.... any new 7.3's are $246.26 each, so stock up while ya can :)

That price is new from Ford......do you have them for the 6.6 D Max?......they go for $830 each new from GM

bottom line.....these new trucks are so expensive to fix your afraid to own one after the warranty is done......that gets to be very expensive for something that is not a daily driver and just sits in the driveway most of the time......thats where Im at.

Im only towing around 10,000......you can get an old gasser and fix it up and have 10gs into it that can do the job and let it sit in the driveway and who cares.......15,000 is another matter though

Stil interested in hearing of your MPG figures when towing and weights your towing. As before stated I run an 86 F350 dually 460 gas. Economy towing hass been anywere from 8 to 12 MPG. Towing the boat 14000 lbs it has done the best so far. My 8 x 18 trailer is the worst. I dont use it for daily driving if its driven its because a truck is needed to do the job.

of course I do... $511.00 new outright or $227.50 new exchange, how many ya want ?? :)

Every time I read mpg's in the high teens or low 20s, I ask my self if going all out on mods is worth it. I have an 06 F350 6.0 410 gears (changed from 373) 37" tires 4" turbo back exhaust, cold air intake and I have not seen better than @12 mpg.
The only thing I love about this truck is that I have towed my boat and @2600 lbs cargo and went up the grades with no problem,and I know no gas big block anything can do that.

I will add a gauge kit and look for something I can remove and leave no footprints when I take it for service. I will pray for better mpgs after that.

I used a Superchips programmer, replaced the air intake with an airraid, and replaced the manifold and exhaust on a 2004 Excursion and went from 14.3 mpg to 17.0 mpg set on "economy" with mild driving and a combination between around town and highway; however, the reprogramming changes settings and suspends the rev limiters such that I think it increases wear and sacrifices engine longevity significantly. The smaller turbodiesels are not made to be reprogammed like a heavy duty truck motor. I got rid of that vehicle at 66K recently because the reprogramming was clearly taking a toll. (It did have unbelievable performance when set for this but I certainly did not beat on it!)