Transmission (mechanics)
![Gears from a five-speed + reverse gearbox from the 1600 Volkswagen Golf (2009).](/Images/godic/202501/16/Cambio_H4131.jpg")
![Single stage gear reducer.](/Images/godic/202501/16/Gear_reducer4131.gif")
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![The main gearbox and rotor of a Bristol Sycamore helicopter](/Images/godic/202501/16/Helicopter_Bristol_171_Sycamore_main_gear_box_and_rotor_head4131.jpg")
A transmission is a machine that consists of a power source and a power transmission system, which provides controlled application of the power. Often the term transmission refers simply to the gearbox that uses gears and gear trains to provide speed and torque conversions from a rotating power source to another device.