The purpose of a vehicle's transmission is delivering the right amount of power to the wheels. To do this, the pistons move the crankshaft at a fixed speed. You can speed up the crankshaft by pressing the accelerator, but the rate at which it accelerates does not change. This is not ideal because you need acceleration when you've just started the car or are traveling up a hill and do not need as much acceleration when you are going down a hill or are cruising on a highway.
Find the engine's pinion gear. This is the gear that the crankshaft turns when the pistons fire. Count the number of teeth on it.
Find the ring gear. This is the gear attached to the transmission that the pinion gear turns when it is engaged. Most manual transmissions have six: five forward gears and one reverse gear. Automatic transmissions usually have five: four forward gears and one reverse gear.
Count the number of teeth on the ring gear.
Divide the number of teeth on the ring gear by the number of teeth on the pinion gear. The higher the number, the higher the ratio, and the better equipped the gear is for acceleration.
