A planetary transmission for selectively shifting among four forward speed ratios includes a first ring gear secured to a drive shaft and encircling a single planet carrier which is secured to the driven shaft. The first ring gear meshes with a carrier journaled first planet gear set which meshes with a driven shaft-encircling first sun gear. The first planet gear set further meshes with a carrier journaled second planet gear set which has integrally connected thereto a third planet gear set. The third planet gear set meshes with a second sun gear and an encircling second ring gear. First, second, and third brakes are respectively connected to the second ring gear, the first sun gear, and the second sun gear to stop and allow rotation of said gears to provide three forward speed ratios between drive and driven shafts. A clutch is provided between the second sun gear and the planet carrier to selectively cause common rotation thereof to provide a fourth forward speed ratio.
A planetary gear transmission having at least two different gearing diameters, the pinions of which are journalled independently of each other so that they can have a large gear ratio step between them; and a multi-speed transmission including first and second planetary gear sets, the second of which sets is the planetary gear transmission having the two different gearing diameters journalled independently of each other. In the multi-speed transmission, the gear ratio steps of the second planetary gear set each exceed the highest gear ratio of the first planetary gear set.
