I am a new member and this is my first posting, be gentle. I have a 98. 5 24v auto 1-ton 4x4 dually,with 110,000 miles. the only mod to the truck is a K&N air filter. I usually run the truck empty but several times a year I pull a 12,000 lbs boat any where from 200 to 1500 miles round trip. I am...