Automatic transmission with overdrive

Claim 1

In an automatic transmission with overdrive for use in automotive vehicles particularly adapted to have parts thereof interchangeably utilized in other transmissions not including overdrive, the combination comprising: a torque converter consisting of a pump impeller, stator vanes, and turbine vanes, and including a turbine shaft for said turbine vanes having an output end; an overdrive gear mechanism having an overdrive input shaft, and a planetary gear unit controlled by a first frictional engaging means coupled to said overdrive input shaft, said overdrive gear mechanism providing a gear reduction ratio of not more than 1; an underdrive gear mechanism having an underdrive input shaft, and a plurality of planetary gear units which are coupled through the medium of a second frictional engaging means to said underdrive input shaft and controlled by said second frictional engaging means and a plurality of other frictional engaging means, said underdrive gear mechanism providing gear reduction rates of not less than 1; said underdrive gear mechanism being structured to be coupled in direct driving engagement with said torque converter in the absence of said overdrive gear mechanism; said torque converter, said overdrive gear mechanism and said underdrive gear mechanism being separably segmented and fastened together by simple fastening means; a torque converter housing, an overdrive case, and a transmission case separately provided for said torque converter, said overdrive gear mechanism and said underdrive gear mechanism, respectively; said overdrive gear mechanism being positioned between said torque converter and said underdrive gear mechanism, with said overdrive input shaft and said output end of said turbine shaft being joined together by a splined connection; said overdrive input shaft and said underdrive input shaft being positioned in axial alignment with each other; a cylindrical extension formed on said torque converter housing with a given inner diameter; said overdrive case being of a cylindrical form and having an outer diameter which is substantially equal to said given inner diameter of said torque converter housing extension; said transmission case also having a cylindrical extension with an inner diameter substantially equal to both said given inner diameter of said torque converter housing extension and said outer diameter of said overdrive case; said overdrive case being fitted in said cylindrical extension of said torque converter housing and in said cylindrical extension of said transmission case, with said torque converter housing, said overdrive case and said transmission case being fastened together by a plurality of bolts extending therethrough; said torque converter and said underdrive gear mechanism being each structured, respectively, of a standardized configuration enabling each to be selected from a plurality of other identical units produced by mass production techniques whereby parts useful in said automatic transmission may also be used in other automatic transmissions not including an overdrive gear mechanism.