Subaru designed the 6-speed manual transmission with fourth, fifth, and sixth gears having overdrive ratios. These gears turn the driveshaft faster than the gears rotate, which helps to improve fuel economy.
Photo: Mike Mattingly
Also, using six speeds instead of five allows a larger ratio coverage, with first and sixth gear ratios beyond those available on the five-speed transmission. The 6-speed design helps reduce fuel consumption, improves drivability, and contributes to a quieter ride at high speeds because engine speed is reduced.