Buying new or used truck

I realized big difference between 3.42 and 3.55. 3.55 can gain more speed on uphill compared to 3.42.

 

Not ideal... Lo pro 22's are the best for fuel mileage. Is 5th wheel height not an issue for you ?

You don't need to have them spec a direct trans , as was stated 11th in a 13 or better 16th with an 18 speed will have you in direct ratio and leave you a couple ( bat outa hell ) extra gears on top.

 

On a regular 13 speed 11th gear is a 1 to 1 ratio. One turn of the input is one turn of the output.
That's how guys get away with running direct drive rear end ratios ( pretty much anything that starts with a 2 ) without swapping out for true direct drive transmissions. They just run around in 11th on the hwy and really never use 12th or 13th. Basically you end up with an 11speed direct. The practical difference is that your low gear start-ability wont be quite as good as it would be with a normal 10 speed direct trans. ( this is why I would prefer an 18 as it has a very slightly lower bottom gear )

As long as you aren't running off road or over 80000 people don't complain about the start-ability factor so it can't be too bad.

This is gaining popularity with those trying to save every drop of fuel.