If I remember right the first automatic put in GM trucks was the 4 speed hydramatic,which was a very good transmission.Most people shied away from automatics in trucks, at that time. I had a 1953 Olds with the 4 speed hydramatic and it was very fast for its time.The Powerglides were a two speed automatic,and were not much for speed when installed with the old six bangers.however they were great when driving on snow and ice.As Chevy later on went with the small block V/8s the Powerglides worked out pretty good,course that was a lot more power.The Buick Dynaflow was also a slow two speed automatic,but with the straight 8 motors they got around pretty good.The older ones you are referring to,were the first automatics of that time and most people who bought them were not looking for performance.It was the same with Fords they had the Fordomatics, Mercomatics,etc.It was the early to mid 60s before Chevy started using the hydramatic units.Whereas Pontiac,Olds,and Cadillac started using hyramatics in the late 40s and early 50s. In fact Oldsmobile started using hydramatics in 1941,and I believe Cadillac also.
