The Powerglide's a two speed automatic transmission designed by General Motors. It was available primarily on Chevrolet automobiles from 1950 through the early 1970s, although some Pontiac models also used this automatic transmission. There were two primary versions of the Powerglide. The Powerglide transmission introduced in 1950 had a cast iron case and's known as the "Cast Iron Powerglide". The "Cast Iron Powerglide" and was used until 1963, when it was revamped as "Aluminum Powerglide" whe… (More on Powerglide)