The transmission system in a vehicle is responsible for transferring power from the engine to the wheels and matching the engine speed to the desired speed of the vehicle, which is controlled by the driver. The transmission helps the vehicle to accelerate, decelerate, and maintain a consistent speed while driving.
However, it's worth noting that the exact mechanism of how a transmission works may vary depending on the type of vehicle and transmission system. Some vehicles have manual transmissions where the driver manually selects the gears, while others have automatic transmissions where the gears are selected automatically by the transmission system based on the vehicle's speed and load. Additionally, some vehicles may have continuously variable transmissions (CVT) which use a belt and pulley system to provide an infinite number of gear ratios.