How do 3.27 gears rob fuel mileage? My '94 Ranger 4.0 Auto 4x4 has 3.27 gears with 235/75 R 15 tires and I can get 23-25 mpg highway out of it on a regular basis, I was able to get 27 mpg once, but have not been able to since. My parents '94 Explorer is the same way, 4x4 4.0 Auto with 3.27 gears...