First of all, I never plan to tow 18,000 lbs. I have decided that I will never own another trailer as heavy as the one I have now (14,400 lbs.).
Secondly, as I said before, I have driven big trucks most of my adult life. If you tell me you are pulling 18,000 lbs (which incidentally is way overloaded for your truck or any other 250/2500 series truck) and your truck never shifts down, you are either towing on very flat land or are very late for April Fools Day.
I have owned a lot of gas and diesel powered truck in my life and have towed with both. I have never had any problem towing what I wanted with a gas or diesel. If you prefer diesel and have no problem shelling out the extra money, I have no problem with that, but with current prices, I am looking to go back to a gas powered truck.
