why would you want to go with a 4.56 gear in the rear of your 2wd truck? do you have a very tall tire on there? I would go with either a 3.92 or a 4.10 on your truck. The higher the numerical number of the gear is the better you accelerate but you run out of gear sooner and your gas milage on the highway is going to go down alot. I went from 3.08s to 3.73s in my ranger and saw a decrease from 22mpg to 17mpg on the highway. How tall of a tire are you going to run in the back of you truck?