Super Turbine 300

The Super Turbine 300 (abbreviated ST-300) was a two-speed automatic transmission built by General Motors. It was used in various Buick, Oldsmobile, and Pontiac models from 1964-1969. It was the same transmission marketed under different brand names by each division including ST-300 by Buick, Jetaway by Olds and simply Automatic by Pontiac.

The ST300 had a three-element torque converter, a front and rear multiple-disc clutch pack, and a compound planetary gearset with a front band and a clutch pack for reverse and manual low gear. The unit was cooled with a small auxiliary oil cooler located beneath the engine radiator. It had a die cast aluminum case, and weighed 152 lb (69 kg).

It was programmed to start in low gear, providing a gear ratio of 1.765:1 plus the additional low-speed multiplication of the torque converter. The shift pattern was Park-Reverse-Neutral-Drive-Low. In Drive at full throttle, it would upshift from low gear to high gear at 60–65 mph (97–105 km/h).

From 1964-1967, Buick and Oldsmobile versions of this transmission used a torque converter with a variable-pitch stator called Switch-Pitch by Buick and Variable Vane by Olds. The stator blades moved from high to low position by an electrical solenoid and a stator valve, controlled by a switch on the throttle linkage. At light to medium throttle, the stator blades were at 32°, providing a torque multiplication of 1.8:1 and a converter stall speed of approximately 1800 rpm. At ⅔ to full throttle, the blades switched to the 51° high position, giving torque multiplication of 2.45:1 and a stall speed of approximately 2300 rpm. The blades were also set to the high position at idle to limit creep when stopped in Drive. The variable-pitch stator was eliminated after 1967. This feature was not used on the Pontiac versions of this transmission.

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