US Patent 7597644 Nine or ten speed split clutch countershaft automatic transmission

A combination countershaft and planetary gear set transmission is provided that achieves at least nine forward speed ratios and two reverse speed ratios. The transmission includes a main shaft operatively driven by a transmission input member as well as first and second countershafts with each countershaft spaced apart from and substantially parallel to the main shaft. The countershafts utilize a split clutch arrangement in which one of the clutches is cantilevered off the countershaft, allowing the size of the countershaft as well as an intermediate support plate to be removed, reducing parts complexity, material and overall length of the transmission.