If I were changing the axle gearing in that truck, I would change to 4.56 or 4.88. There isn't enough difference between 3.73 and 4.10 to justify the cost of the change, which is $1500-2000 on a 4x4.
I know this because- I changed from 3.55 to 4.56 in my 4x4 F350 several years ago, and added a locking differential in the rear at the same time. Cost was $2000, which included the $300 differential part.
On the ratio, I wish I had changed to 4.88 instead of 4.56. However, without an overdrive gear in the transmission (C6 auto), 4.56 was as low as I dared to go. 4.56 was a good decision for the circumstances, but I still wish I'd had an overdrive gear and gone with 4.88's instead.
You got a great truck there with only 27,000 miles on it! :b. Sounds like maybe a government auction truck?
My '92 F350 was originally a federal government truck. I got it with only 37,000 miles on it. It's been a great truck for the past 14 years I've owned it. :)
Toyhauler RV trailers are built with axles far forward, such that most of the garage area is behind the axles, rather than in front of them. Therefore, when you load something heavy in the garage area, the cargo weights the rear of the trailer and lightens the tongue.
A good aftermarket receiver hitch is a small amount of money in the scheme of things and a very good investment in your truck. I would put that quality, American made Curt hitch on the truck and have peace of mind that the factory hitch is not quietly fatiguing and cracking without my knowing, as I happily tow my load.
I put a Curt Magnum V heavy duty hitch on my F350 years ago when I first got it. Have towed many trailers with very heavy hitch weights and the hitch is still in perfect condition, never a crack or bend.
I've put a few Curt hitches on my trucks (2 F350's, a Ranger, and an E350, so far. All but the E350 got both front and rear hitches, most of them from Curt). They build a quality product, and it's actually made here in America. :D
Can't say that anymore about the Reese/Drawtite/Fulton/HiddenHitch/TowPower line of products anymore. They're made in China these days. :(. Their product is probably still ok, but I have a thing about keeping my money in my own country and employing my fellow American workers, whenever possible.
