- Super Turbine 300
The Super Turbine 300 (abbreviated ST-300) was a two-speed
automatic transmissionbuilt by General Motors. It was used in various Buick, Oldsmobile, and Pontiacmodels from 1964through 1969. Oldsmobile called this transmission Jetaway, while Pontiac designated it as TempesTorque through 1966 and then Two-Speed Automatic from 1967 to 1969.
The ST300 had a three-element
torque converter, a front and rear multiple-disc clutchpack, and a compound planetary gearsetwith 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 aluminumcase, and weighed 152 lb (69 kg).
It was programmed to start in low gear, providing a
gear ratioof 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 (99-104 km/h).
1964to 1967Buick 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 solenoidand a stator valve, controlled by a switch on the throttlelinkage. 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 two-thirds 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.
The Super Turbine 300 (Jetaway) was introduced for the
1964 model yearas a replacement for the earlier Buick Dynaflowand Oldsmobile/Pontiac Roto Hydramatictransmissions. It was the only automatic offered on GM A platformcars ( Buick Skylark, Oldsmobile Cutlass, and Pontiac Tempest) through 1966, and was available on the full-sized Buick LeSabreand Oldsmobile Jetstar 88/Delmont 88 as a cheaper alternative to the three-speed Turbo-Hydramatic. From 1967 to 1969, the Super Turbine 300 was also available on the sporty Pontiac Firebirdwith the overhead cam in-line six-cylinder (230 and 250 cubic inches) or small V8 engines (326 and 350 cubic inches).
The Super Turbine 300 was discontinued entirely after the
1969model year in favor of the TH400 and lighter TH350 Turbo-Hydramatic, the latter using the Super Turbine 300's tailhousing.
Super Turbine 300s were the first GM automatics to incorporate multi-case bellhousings (ST300s were bolted behind BOP powerplants along with the Chevrolet inline six) - which were later used with its successors - the THM350 and THM2004R overdrive.
Due to its two-speed with torque converter design, the Super Turbine 300 is often confused with Chevrolet's
Powerglide- which was also a two-speed torque converter transmission, but the fact is the ST 300 was of a completely different design and shared absolutely no parts or components with the Chevy unit.
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