abstract:Dynaflow was the trademark name for a type of automatic transmission developed and built by General Motors' Buick Motor Division from late 1947 to mid-1963. The Dynaflow, which was introduced for the 1948 model year only as an option on Roadmaster models, received some severe early testing in the M18 Hellcat tank destroyer, which were built in Buick's Flint, Michigan assembly plant during World War II.