Patent ID: 7488268

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 and third planetary gear sets within the cavity, each planetary gear set having a sun gear member, a ring gear member, and a carrier member rotatably supporting a plurality of pinion gears intermeshing with both the sun gear member and the ring gear member; wherein the transmission casing and the planetary gear sets define five zones within the cavity, including a first zone extending axially from the first end wall to one of the planetary gear sets, a second and a third zone each extending axially between different adjacent pairs of the planetary gear sets, a fourth zone extending axially from another one of the planetary gear sets to the second end wall; the first, second, third, and fourth zones extending radially to an outer periphery of a radially-outermost one of the ring gear members, and a fifth zone bordering the first, second, third and fourth zones and extending radially outward to the housing portion and axially between the first and second walls; an interconnecting member continuously interconnecting for common rotation the carrier member of the first planetary gear set, the sun gear member of the second planetary gear set and the ring gear member of the third planetary gear set; six torque-transmitting mechanisms located in at least one of the zones; a radially-extending structural member connected to the transmission casing; wherein the sun gear member of the first planetary gear set is continuously grounded to the transmission casing via the radially-extending structural member; wherein at least one of the torque-transmitting mechanisms selectively grounds one of the members of one of the planetary gear sets to the transmission housing via the radially-extending structural member; wherein the six torque-transmitting mechanisms include four rotating-type clutches and two stationary-type clutches; and wherein the two stationary type clutches ground the carrier members of the first and second planetary gear sets to the transmission housing via the radially-extending structural member; and wherein the six torque-transmitting mechanisms are selectively engagable in different combinations to provide eight forward speed ratios and a reverse speed ratio between the input member and the output member.