2017 Ford Super Duty 6.7 3.73 Gear Swap Originally published in September 2010 and Updated in Oct 2021. Ofttimes overlooked, optional gear ratios play a central role in pickup truck performance. If the axle ratio is too tall, the truck may seem to lack power, especially when climbing hills. This may be corrected with a numerically higher axle ratio, often at the expense of unladen highway fuel economic system. Consider that with a 3.31 beam ratio, the driveshaft turns 3 1/3rd times for every revolution of the rear wheel. With a 4.30 ratio, it turns 4 1/3rd times for every revolution of the rear bicycle. The numerically higher gear ratio (in this case, 4.30) increases wheel torque and improves acceleration from low speeds. Merely the engine does have to run faster to achieve a given speed. Video: How a Differential Works Selecting the best gear ratio tin can be