Transmission Internals

A standard vehicle gearbox is made up of five to six sets of gears plus a number of gear trains (basically belts or chains going around the outside of two or more gears) that allow the driver to change how much power is transmitted to the car without affecting the engine's speed.

In other words, a car transmission ensures that your engine is spinning at the appropriate speed for your needs, without overspeeding or underspeeding. It also ensures that your wheels receive the proper amount of power. Any automobile would be impossible to start and stop without a gearbox and completely unreliable.