Gm 700r4 transmission plus#
Gm 700r4 transmission series#

Some 'Heavy Duty' THM350s were also designated THM375-B.Īnother variant is the 3L80HD, often referred to as a Turbo 475. Somewhere in the Mid-80's Chevrolet C10 Pickups could also come equipped with a THM375. THM375s were found in some 1971-76 Buick Lesabres and Oldsmobile Delta 88s with the 5.7 liter V-8. Internally, the clutch packs originally had fewer friction plates. They used a Chevrolet bolt-pattern case with a longer 27 spline output shaft inside a matching tailhousing cast with a '375-THM' or 'TH375' identifier. A variant known as a THM375 is a THM400 built to mate to the smaller driveshaft yokes typically used for THM350 applications. Vehicles originally equipped with the Switch Pitch ST300 can be identified by their 'Park R N D L2 L1' gearshift selector.Ī Hydra-Matic 3L80 transmission, produced between 19, at the Ypsilanti Automotive Heritage MuseumĪll THM400 units had a 32 spline output shaft. Note: GM had also used a Switch Pitch in the 1955–1963 Buick twin-turbine Dynaflow and the 1964-1967 two-speed Super Turbine 300 used in Buick and Oldsmobile (Pontiac's ST300 didn't get the SP). A Switch Pitch can be identified outside the vehicle (with the torque converter removed) by a narrow front pump spline. A SP THM400 always has an external 2 prong connector, whereas a non-SP may have one or two (mostly one, except two on vehicles equipped with an internal pressure switch for spark timing retard). Many of the BOC (Buick, Oldsmobile, Cadillac) THM400s produced between 19 were equipped with a variable-pitch stator torque converter called ' Switch-Pitch' (SP) these are sought after by collectors and drag racers. The following year, application expanded to Oldsmobile and Pontiac and to some full-sized Chevrolets. First introduced for the 1964 model year under the name 'Turbo Hydra-Matic' in Cadillacs and 'Super Turbine' in Buicks. The THM400 can be visually identified by an oil pan number four shown at General Motors Transmission Pans. Super Turbine 400 / TH400 / THM400 / THM375 / 3L80 / 3L80HD Turbo-Hydramatic 400 Transmission Starting in the early 1980s, the Turbo-Hydramatic was gradually supplanted by four-speed automatics, some of which continue to use the 'Hydramatic' trade name.Īlthough the Turbo Hydra-Matic name alludes to the original Hydra-Matic developed by General Motors' Cadillac division in the late 1930s, the two transmissions were not mechanically related. By 1973, THM units had replaced all of GM's other automatic transmissions including Chevrolet's Powerglide, Buick's Super Turbine 300, and Oldsmobile's Jetaway. The Buick version, which followed shortly thereafter, was known as the Super-Turbine 400. In its original incarnation as the Turbo-Hydramatic 400, it was first used in the 1964 model year in Cadillacs.

Gm 700r4 transmission series#

The Turbo-Hydramatic or Turbo Hydra-Matic (THM) series was developed to replace both the original Hydra-Matic models and the Buick Dynaflow.

Gm 700r4 transmission plus#

These transmissions mate a three-element turbine torque converter to a Simpson planetary geartrain, providing three forward speeds plus reverse. Turbo-Hydramatic or Turbo Hydra-Matic is the registered tradename for a family of automatic transmissions developed and produced by General Motors. 3-speed longitudinal automatic transmission