Transmission (mechanical device)

Hydraulic automatic transmission (cutaway view)

Epicyclic gearing diagram, as used in hydraulic automatic transmissions

A transmission (also called a gearbox) is a mechanical device which uses a gear set—two or more gears working together—to change the speed or direction of rotation in a machine.^[1]^[2] Many transmissions have multiple gear ratios, but there are also transmissions that use a single fixed-gear ratio.

Most currently-produced passenger cars with gasoline or diesel engines use transmissions with 5–8 forward gear ratios and one reverse gear ratio. Electric vehicles typically use a fixed-gear or two-speed transmission with no reverse gear ratio.

^ J. J. Uicker; G. R. Pennock; J. E. Shigley (2003). Theory of Machines and Mechanisms (3rd ed.). New York: Oxford University Press. ISBN 9780195155983.
^ B. Paul (1979). Kinematics and Dynamics of Planar Machinery. Prentice Hall.

[:0-1] J. J. Uicker; G. R. Pennock; J. E. Shigley (2003). Theory of Machines and Mechanisms (3rd ed.). New York: Oxford University Press. ISBN 9780195155983.

[2] B. Paul (1979). Kinematics and Dynamics of Planar Machinery. Prentice Hall.

[1]

[2]