Gearboxes are used to balance the engine’s RPM (Revolutions per Minute) and ensure that there is not too much or too little power being transferred to the wheels at any given time. Without a gearbox, a car’s engine would quickly overheat or the vehicle would be unable to reach its specified car engine capacity. Gearboxes also help to reduce unnecessary fuel consumption, as different gears use fuel at different levels – this is because the higher the gear, the lower the revs and the less fuel is required to move the vehicle.