One of the first American carmakers, Oldsmobile was founded all the way back in 1897. It built the world's first mass-produced car in 1902 and went under General Motors ownership in 1908. As a division of GM it slotted above Chevy and Pontiac, but below Buick and Cadillac. The brand was shutdown in 2004, but it remains famous for its groundbreaking technology and designs. Oldsmobile introduced more than 20 industry-first technologies, including the first production fully automatic transmission. It's called the Hydra Matic and it was introduced for the 1940 model year.
The Hydra Matic debuted on the Oldsmobile Series 60, a full-size automobile offered in a variety of body styles. Although it wasn't designed specifically for Olds, the brand was chosen because it produced more cars than Cadillac at the time, meaning it provided a better test base. The Hydra Matic became an option on Cadillacs for the 1941 model year.
The Hydra Matic later found its way into Pontiac models, but other GM divisions, like Chevrolet and Buick, chose to develop their own automatics. The Hydra Matic was so successful that by 1949 more than one million cars fitted with this gearbox were sold. As a result, companies that didn't have the resources to develop their own automatic bought Hydra Matics from GM in the 1950s. Lincoln, Rambler, Nash, Hudson, Kaiser, Frazer, and Willys are among them. In 1952, Rolls-Royce also purchased a license to produce the Hydra Matic for Rolls-Royce and Bentley luxury cars, using them until 1967.
Granted, the old Hydra Matic feels ancient compared to modern automatic transmission, but it was a big deal back in the 1940s. Here's one of the first commercials that advertised the then-innovative gearbox.