When General Motors opened the Detroit Transmission plant in Livonia, MI, in 1949, the 1.5-million-square-foot facility symbolized the resounding success of the most popular component in American automobiles—the Hydra-Matic Drive transmission. Millions of buyers, anxious to dump prewar clunkers and the tedious manual shifting that propelled them, wanted cars that automatically cruised through the gears. GM was ready to supply them.

Introduced as a $57 option on 1940 Oldsmobiles, Hydra-Matic was an instant sensation. The company built 900,000 of the four-speeds over the next nine years at a rickety, six-story plant on Riopelle Street in Detroit, including 55,000 for World War II tanks, tank destroyers and armored vehicles. During that time, Hydra-Matic Drive became synonymous with automatic shifting; there were no serious competitors.