Semi-automatic transmission
A semi-automatic transmission is a multiple-speed transmission where part of its operation is automated, but the driver's input is still required to launch the vehicle from a standstill and to manually change gears. Semi-automatic transmissions were almost exclusively used in motorcycles and are based on conventional manual transmissions or sequential manual transmissions, but use an automatic clutch system. But some semi-automatic transmissions have also been based on standard hydraulic automatic transmissions with torque converters and planetary gearsets.
Paddle shifter on a car.
Bollée Type F Torpedo with gear shift ring located inside the steering wheel
Illustration of Saab's Sensonic clutchless manual transmission system.
Transmission (mechanical device)
A transmission 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. Many transmissions have multiple gear ratios, but there are also transmissions that use a single fixed-gear ratio.
Hydraulic automatic transmission (cutaway view)
Transmission for a Bristol Sycamore helicopter
Mazda M5OD manual transmission (viewed from the engine side)
Transmission internals for a 2009 Volkswagen Golf