Patent ID: 8292767

Claim:
A powertrain comprising: an engine; and a transmission having: a transmission input member; a transmission output member; a first, second, third and fourth planetary gear set each planetary gear set having a sun gear member, a ring gear member and a planet carrier member supporting a plurality of planet gears each configured to intermesh with both the sun gear member and the ring gear member, wherein the transmission input member is continuously interconnected with the planet carrier member of the second planetary gear set, and the transmission output member is continuously interconnected with the planet carrier member of the fourth planetary gear set and the planet carrier member of the third planetary gear set, and wherein the sun gear member of the first planetary gear set is continuously interconnected with the sun gear member of the second planetary gear set, the ring gear member of the second planetary gear set is continuously interconnected with the sun gear member of the third planetary gear set, the planet carrier member of the first planetary gear set is continuously interconnected with the ring gear member of the fourth planetary gear set; a first clutch selectively engageable to interconnect the sun gear member of the fourth planetary gear set to the planet carrier member of the second planetary gear set and the transmission input member; a second clutch selectively engageable to interconnect the sun gear member of the fourth planetary gear set to the sun gear member of the third planetary gear set and the ring gear member of the second planetary gear set; a third clutch selectively engageable to interconnect the sun gear member of the fourth planetary gear set to the ring gear member of the third planetary gear set; a first brake selectively engageable to interconnect the sun gear member of the first planetary gear set and the sun gear member of the second planetary gear set to the transmission housing; a second brake selectively engageable to interconnect the ring gear member of the first planetary gear set to the transmission housing; and wherein the clutches and brakes are selectively engageable to establish at least eight forward speed ratios and at least one reverse speed ratio between the transmission input member and the transmission output member; and a differential connected between the transmission output member and a pair vehicle axles for receiving an output torque from the transmission and distributing the torque to the pair of vehicle axles.