A planetary transmission for selectively shifting among four forward speeds includes a first ring gear secured to a drive shaft. The first ring gear drives a compound planetary gear set which is journaled on a driven-shaft-connected planet carrier. A first planet gear set of the compound planetary gear set meshes with a carrier-journaled, third planet gear set which meshes in turn with a second ring gear. The first planet gear set further meshes with a first sun gear which is concentric with the first ring gear and which encircles and is clutchable to the driven shaft to provide one forward speed ratio between drive and driven shafts. A second plane gear set of the compound planetary gear set meshes with a second sun gear which is coaxial with the first sun gear and concentric with the second ring gear. First, second, and third brakes are respectively connected to the second ring gear, the second sun gear, and the first sun gear to stop and allow rotation of said gears to provide three additional forward speeds.
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.
