This article has multiple issues. Please help or discuss these issues on the(
A semi-automatic transmission (also known as a clutch-less manual transmission, auto-manual, automated manual transmission, trigger shift, flappy-paddle gear shift or paddle-shift gearbox) is an
It allows convenient driver control of gear selection. For most of automotive history, automatic transmissions already allowed some control of gear selection using the console or
Some transmissions allow the driver to have full control of gear selection, though most will intervene to prevent engine stalling and redlining by shifting automatically at the low end and/or high end of the engine's normal operating range.
A clutch-less manual facilitates gear changes by dispensing with the need to press a
In the 1930s, automakers began to market cars with some sort of device that would reduce the amount of clutching and de-clutching and shifting required in stop and go driving. Most typically, a fluid coupling or a centrifugal clutch replaced the standard manual clutch to allow for stop and go driving without using the clutch pedal every time the car was brought to a stop. More sophisticated systems allowed for shifting while driving without using the clutch, and some systems did away with the clutch pedal altogether. Semi-automatic transmissions were phased out as technology advanced and automatic controls were developed to take care of changing gear ratios. Smaller, lower powered cars used Semi-automatic transmissions with a dry clutch because the mechanical connection offered a more efficient powertrain compared to a fluid coupling.
Another early semi-automatic transmission was the Sinclair S.S.S. (synchro-self-shifting) Powerflow gearbox. which was applied to Huwood-Hudswell diesel mines locomotives. It was also applied to some road vehicles.