I'm seriously considering purchasing a 2011 F350 6.7 SRW supercab long bed lariat 4 x 4 The truck has all the creature comforts but the truck is geared with 3.31 gears. The window sticker shows a tow package but the gearing has me concerned. I occasionally (a few times a month) tow a 14K dump trailer. Loaded with skidsteer and backhoe attachment weighing in about 12K. Any thoughts on climbing grades and overworking the truck in the process. Thanks for your input.

 

here are the 2012 towing stats would assume 2011 are close:
2012 Ford Super Duty | View Towing Specifications | Ford.com

would think 12 to 14 k would be fine...

 

That truck probably has a 6 speed transmission that will be easy enough to select the right gear for hills. Remember, a gear is a gear is a gear. Once you get rolling, it really make no difference whether it is in the tranny or in the diff other than your convenience in selecting it.

 

My son's new Dodge has the 3.42 rear end in it with the H/O package producing 800# of torque.
I was pulling a 24' bumper pull trailer behind it and was stopped at a signal.
Knowing it narrowed down to 1 lane a couple of hundred yards ahead, I was in the outside lane and was waiting for the line of cars in the inside lane to pass. Unfortunately, the first car was going the same slow speed as me for way too long, so I decided to jump on the "gas" to pass him.

Even with about 45# in the rear tires, it spun the tires without effort.
I was shocked that any truck with that high of a gear ratio could do that, not to mention the strength of these rear ends.

It just goes to show you that these engineers most know what they're doing when they drop in these high gear ratio's with the enormous amount of torque now created.