From Longman Dictionary of Contemporary Englishautomatic transmissionˌautomatic transˈmission noun [countable, uncountable] TTCa system that operates the gears of a car without the driver needing to change them
Examples from the Corpus
automatic transmission• Yes, it had a heater and, what's more, you could even have air conditioning and automatic transmission.• It did not have Powerglide automatic transmission.• Meanwhile, the Mondeo becomes the first Ford to use a new electronically-controlled four-speed automatic transmission system.• The new company will market the transmissions but will subcontract the manufacture of the automatic transmission.• It turns in very firmly, with surprising power response, when ordering the automatic transmission to think quickly.• Most of you probably will want automatic transmission, which adds another $ 975. 