That was accomplished by the Detroit Transmission Division during development of the Model 315 Dual Coupling Hydra-Matic four speed transmission, which was brought to market for 1956 Cadillac, Oldsmobile and Pontiac models with great success. Chevrolet did not have the benefit of Detroit Division's experience in aluminum case casting, and engineering errors were made, exacerbated by a lack of pre-production testing.
The successful outcome was accomplished by the Detroit Transmission Division while working on the Model 315 Dual Coupling Hydra-Matic four-speed transmission, which was successfully launched for 1956 Cadillac, Oldsmobile, and Pontiac models. Chevrolet, however, lacked the benefit of Detroit Division's expertise in aluminum case manufacturing, resulting in engineering flaws that were exacerbated by a lack of pre-production testing.