Hydramatic (also known as Hydra-Matic) is an automatic transmission developed by General Motors Corporation's Oldsmobile Division, the Hydramatic was the first mass-produced fully automatic transmission developed for passenger automobile use. The Hydra-Matic transmission was introduced by Oldsmobile in 1939 for the 1940 model year, one year before Cadillac.
An automatic transmission (AT) or automatic gearbox is a multi-speed transmission used in motor vehicles that does not require any input from the driver other than throttle position to change forward gears under normal driving conditions.
The 1904 Sturtevant "horseless carriage gearbox" is often considered to be the first true automatic transmission. The first mass-produced automatic transmission is the General Motors Hydramatic four-speed hydraulic automatic, which was introduced in 1939.
The M18 Hellcat (officially designated the 76 mm Gun Motor Carriage M18 or M18 GMC) was a tank destroyer used by the United States Army in World War II and the Korean War. Despite being equipped with the same main gun as some variants of the much larger Sherman tank, the M18 attained a much higher top speed of up to 55 mph (89 km/h) by keeping armor to a minimum, and using the innovative Torqmatic automatic transmission.
The M18 Hellcat was the culmination of the development of various prototypes of fast tank destroyers dating back to 1941. Entering production in summer 1943, the M18 first saw combat service in spring 1944. The M18 served primarily in Western Europe, but was also present in smaller numbers in Italy and the Pacific. Production continued until October 1944, with 2,507 built.