With there are four axle ratio choices with the SRW and diesel. I have no idea which is better.....or for what reason. Any input? See below.

i always like to assume the most expensive option is the best one which i will end up wanting, even if i dont need it.

With the load you will be towing, you definately want the 3.55; and you also want the Locking Rear End for traction on the ramp. (Since I know this won't be a daily driver for you; the fuel mileage is not a concern for said use.)

Since you are looking at 4x4, you will have that in reserve, but there is no advantage to a non-locking axle.

Are you going to send it off and have it changed into an X?

An "X"?

eXcursion

Personally I like the 4.11 gearing for towing at a minimum. Especially towing heavy loads, and a locking/positraction differential is a must. The lower gearing provides for great torque multiplication.

With a 5 and 6 speed transmissions of today, the rear gearing at highway speeds in inconsequential.

Currently I have 4.88 on one vehicle, & with the 35" taller tires on the truck, the final drive ratio is around 4.20-4.30, and 4.56 on another tow vehicle.

I tend to agree, but it looks as thought it may not be available.
(Remember, both the front and rear gears need to match in a 4x4, but Ford knows that.)

The 3.55 is more of a mileage gear than a towing gear. But the new Diesels have a lot more power which can and probably does make up for that.

IF you plan to go to bigger wheels and tires, you most certainly will want a 4.11 gear set. Or at least a 3.73. For these you may have to special order...
... or you can change the gears down the road. It's not a major project. Just gear swap changes in both pumpkins, and some computer adjusting of the torque management and transmission shift points.

Plus being a SRW, there is more surface area for tire contact for more traction too......

The one I've found has the 3.55 Electronic Locking Axle. The other choices (which I deleted from the graphic) are only for the gas engine.

Nort, Buy my 06 ! You will just take it to some shop, take the motor out, rip it apart, change the interior, paint it, lift it or lower it, change the tires and rims, never use it and talk about it forever........for $30K less than new.