The present invention provides for improvements made to the infinitely variable rotary drive transmission U.S. Pat. No. 4,557,161 dated Dec. 10, 1985, having an input member and an output member rotatably mounted to a housing. Two articulated shafts are rotatably mounted on two slides such that the degree of articulation can be varied in infinite increments by operating a lever mounted on the housing. The two articulated shafts are connected rotatably and synchronously. The input member through a substantial speed reduction drives the articulated shafts. The articulated shafts are connected by rods to a pair of cooperating overrunning clutch assemblies mounted on an intermediate shaft which in turn is rotatably mounted on the housing. Another clutch assembly is mounted on the intermediate shaft to restrict its movement to one direction only. The intermediate shaft through a substantial speed increase drives the output member.