There were several variations of the semi-auto used by Chrysler Corp. over about 15 years, late 1930's to mid 1950's. At least one was a vacuum-shifted type, and several names were used for the one with two forward shifter positions, one reverse, and an electric upshift for a total of 4 forward ratios. Dodge called it Gyro-matic, Chrysler called it M-6, and I believe DeSoto called the same setup a "Tip-toe-Matic". All of them had an independent fluid drive bolted to the crankshaft with a manual clutch between the fluid coupling and the transmission. I believe the first full-auto trans was the 2-speed Powerflite in 1955, followed by the cast iron Torqueflite 3 speed a year or two later.
Jerry
