Did you know there was a time when shifting gears manually was your only option? Before 1940, when GM came out with the Hydra-matic in their 1940 Oldsmobile; manual transmissions were pretty much the only option for personal driver vehicles. The Hydra-matic however, was actually not the first automatic transmission to be invented. In 1904 the Sturtevant brothers of Boston created their two-speed transmission, operated by weights and bands. Unfortunately they were not extremely reliable as the weights often flew apart.
In 1934, Reo created the “Reo Self Shifter”. The Reo Self Shifter was actually two transmissions which were connected. One of the systems was shifted manually when a lower gear was needed and the other system shifted automatically in relation to the cars speed.
In 1937, came the “semi-automatic” transmission, Oldsmobile created the Automatic Safety Transmission which was a four-speed. With this transmission, drivers had to depress the clutch and select Reverse, Low or High. Once in Low or High the transmission shifted automatically. In 1938, Buick released a short lived five-speed semi-automatic transmission which was discontinued after only a year due to so many problems.
It wasn’t until 1948 that we began to see hydraulic torque converters like the ones we use today. Buick began to offer the Dynaflow fully automatic transmission. This was a $244 option drivers could select for their Roadmaster. Within a few years about 85% of Buick vehicles were equipped with the Dynaflow transmission. It was used as the model for present-day automatic transmission systems. Soon after the success of the Dynaflow, others began to follow with their own units.