Abstract: A system permitting a wide range of distribution, transmission, and reduction of rotary motion by means of a double epicyclic train. Two crown wheel plates face one another and are freely rotatable, one on a driving shaft and the other on coaxial driven shaft. The shafts also rigidly mount two facing inner planetary conical pinions that are coaxial and concentric with the respective crown wheel plates. Sandwiched between the plates are two sets of satellite pinions; the first set meshing with the crown wheel plates and the second set meshing with the planetary conical pinions. Both sets of satellite pinions freely rotate on cruciform axles. The cruciform axles, in turn, rotate freely about the coaxial driving and driven shafts. The system may be adapted to provide an automatic speed change gear system or, alternatively, a friction clutch system.