4 Wheel Drive/SUVs: gear ratio, gas mileage, gear ratio

Question
i have a stock 05 f 150 4wd crew cab with 373 gears (bad gas mileage).at 70mph 2000 rpm 17 in wheels.i want to drop at least 200 rpm at his speed. what gear would i go to?.i only pull small boat twice a year.
                      thanks johnny

Answer
If it is available, a 3.55 gear ratio is ideal. It has a good pulling ability but also has good highway capability as well. But, make sure you change both front and rear gear sets or damage will result. Gears not maching will cause binding of the front axle and transfer case since the transfer case will be trying to turn at 2 different speeds at the same time and will break! Look into it and this will be fine

Matt