I agree with what everyone is saying. I watch my EGTs. At speed (65-80) i have NO problem pulling in 6th gear. After getting caught behind slower traffic i watch the EGTs and have found that i will run lower temps in 5th gear while accelerating (50-60), I doubt i need to jump down to 5th, but i do it anyways. Just my two cents. It all comes with the feel you get for the truck. Enjoy it, i know i do!