Patent ID: 7824297

Claim:
A multi-speed transmission comprising: a transmission casing having a first end wall, a second end wall, and a housing portion interconnecting the first end wall and the second end wall; wherein the end walls and the housing portion define a cavity; an input member; an output member; first, second, third and fourth planetary gear sets within the cavity, each planetary gear set having a first member, a second member, and a third member; wherein the transmission casing and the planetary gear sets define six zones within the cavity, including a first zone extending axially from the first end wall to one of the planetary gear sets, a second, a third, and a fourth zone extending axially between different adjacent pairs of the planetary gear sets, a fifth zone extending axially from another one of the planetary gear sets to the second end wall; the first, second, third, fourth, and fifth zones extending radially to an outer surface of a radially outermost one of the members, and a sixth zone bordering the first, second, third, fourth and fifth zones and extending radially outward to the housing portion and axially between the first and second walls; wherein the second member of the first planetary gear set is continuously connected for common rotation with the first member of the second planetary gear set; wherein the second member of the second planetary gear set is continuously connected for common rotation with the first member of the third planetary gear set; wherein the second member of the third planetary gear set is continuously connected for common rotation with the first member of the fourth planetary gear set; wherein the third member of the third planetary gear set is continuously connected for common rotation with the third member of the fourth planetary gear set; wherein the third member of the first planetary gear set is grounded to the transmission casing; wherein the input member is continuously interconnected for common rotation with the first member of the first planetary gear set; wherein the output member is continuously interconnected for common rotation with the first member of the fourth planetary gear set; and five torque-transmitting mechanisms located in at least one of the zones and selectively engagable in different combinations, wherein each engaged torque transmitting mechanism interconnects a respective one of the members of the first, second, third, and fourth planetary gear one of the input member, the output member, the transmission casing, and another respective one of said members of the planetary gear sets to achieve eight forward speed ratios and a reverse speed ratio between the input member and the output member.