Editing Automatic transmission (section)

{{Short description|Type of motor vehicle transmission}}
[[File:Automatic transmission cut.jpg|thumb|right|Cutaway view of a 2007 [[Toyota A transmission#AA80EValvetrain|Toyota AA80E]] hydraulic automatic]]
[[File:Ford Escort 1.9 1992-autotrans.jpg|thumb|right|Typical gear selector for an automatic transmission]]

An '''automatic transmission''' ('''AT''') or '''automatic gearbox''' is a multi-speed [[transmission (mechanics)|transmission]] used in motor vehicles that does not require any input from the driver to change forward gears under normal driving conditions.

The 1904 Sturtevant "horseless carriage gearbox" is often considered to be the first true automatic transmission.<ref>{{cite web |url=https://www.autorepairsanantonio.com/40-automatic-transmission-history |title=Automatic Transmissions- A Brief History |website=AutoServiceExperts |year=2003|url-status=live|archive-url=https://web.archive.org/web/20200418231514/https://www.autorepairsanantonio.com/40-automatic-transmission-history |archive-date=2020-04-18}}</ref><ref name=hearst>{{cite magazine|url=https://www.caranddriver.com/research/a31884931/what-is-an-automatic-car/ |title=What is an Automatic Car?|author=Hearst Autos Research|magazine=Car and Driver |date=13 April 2020<!--from page source-->|url-status=live|archive-url=https://web.archive.org/web/20200417081714/https://www.caranddriver.com/research/a31884931/what-is-an-automatic-car/ |archive-date=2020-04-17}}</ref>{{Failed verification|date=March 2024|reason=Source 1 does not mention the Sturtevant transmission. Source 2 cites source 1.}} The first mass-produced automatic transmission is the General Motors ''[[Hydramatic]]'' two-speed hydraulic automatic, which was introduced in 1939.

Automatic transmissions are especially prevalent in vehicular [[drivetrain]]s, particularly those subject to intense mechanical acceleration and frequent idle/transient operating conditions; commonly commercial/passenger/utility vehicles, such as [[bus]]es and [[waste collection vehicle]]s.