TH400
The THM400 can be visually identified by an oil pan number four shown at Transmission pans. It was first introduced for the 1964 model year under the name "Turbo Hydra-Matic" in Cadillacs and "Super Turbine" in Buick's. The following year, application expanded to Oldsmobile and Pontiacs and to some full-sized Chevrolet's as well as Trucks.