The Chevrolet Powerglide automatic transmission had two forward speeds. Its two-speed design used a low gear for starting and acceleration, then shifted into a direct-drive high gear.
Introduced for the 1950 model year, Powerglide was Chevrolet’s first automatic transmission and helped bring automatic shifting to lower-priced cars. Early 1950–1952 versions did not shift automatically from low to high; the driver selected the range manually. From 1953 onward, the transmission could start in low and shift to high automatically.
Powerglide’s simplicity made it durable, but its single upshift eventually became a disadvantage as buyers began preferring three-speed automatics. Chevrolet phased it out after the 1973 model year, replacing it with newer Turbo-Hydramatic units. The transmission nevertheless became popular in drag racing because it has fewer shifting parts and can withstand substantial abuse.
A common mix-up is confusing the two forward speeds with the transmission’s selector positions. Reverse, neutral, park, and low-range positions do not count as forward gears.