Abstract: A gear reduction mechanism wherein a modification of the hypocycloidal principle is used. The planet gear of the hypocycloidal arrangement has at least one-half tooth more or less teeth than one-half the number of teeth on the ring gear. Either the ring gear or a pin reaction plate is permitted to rotate while the other is stationary. The reaction pins disposed on the planet gear travel in straight lines in slots formed in the reaction plate. When the reaction plate is stationary, the ring gear must rotate a very small amount during one complete rotation of the planet carrier to compensate for the tooth difference between the ring and planet gears. When the ring gear is held stationary, the reaction plate is forced to rotate to compensate for the tooth difference.

Abstract: A transmission control for a multi-speed transmission having governor pressure controlled shift valves for controlling interchange of speed ratios. A downshift control valve is disposed in the transmission control between one shift valve and the automatic low speed ratio drive establishing device to prevent automatic downshifting to the low speed ratio from a higher speed ratio, separated therefrom by at least one step, upon sudden discontinuance of or reduction in governor pressure.