The Super Turbine 300, or ST-300, was a General Motors' automatic transmission used on Buick, Oldsmobile and Pontiac vehicles from 1964 until 1969. The two-speed ST-300, commonly found in the Pontiac Tempest and Firebird, the Oldsmobile F85 and the Buick Special, was equipped with a three-element torque converter and a clutch for reverse and manual low gear. The ST-300 automatic transmission, sometimes referred to as the 300THM, is easily identified by locating three visual clues.
View the transmission. The GM ST-300 automatic has a one-piece aluminum case and bell housing. The cast aluminum casing has a smooth texture, unlike the rough surface of a cast-iron transmission housings.
Count the bolts attaching the oil pan to the bottom of the ST-300. The oil pan, located at the bottom of the transmission, has 14 bolts holding it to the transmission case.
Notice the shape of the ST-300 transmission oil pan. According to Charlie Tranny's ST-300 Buick Bottom image, the pan has a square shape, with the driver's-side rear corner on an angle and an extension at the passenger's-side rear corner (see Resource 3).
