what will give me the best milage and or performance. I will be puting a 4000 lb. camper on it and some times pulling a trailer.3:31 or 3:55?

 

Personally, I think the newer trucks have gear ratios that are numerically quite a bit lower than optimum in order to maximize fuel economy. Running down the freeway empty there may be some validity to this, but I always get the numerically highest gears available. It allows you to better utilize the gear spacing in the transmission and gives you better loaded launch power without generating as much transmission heat. If you're looking at a SRW, 3.55 is the lowest you can get. With a DRW I think its 3.73.