US Patent 8002662 Multi-speed transmissions

The transmission has a plurality of members that can be utilized in powertrains to provide at least ten forward speed ratios and one reverse speed ratio. The transmission includes four planetary gear sets, six torque-transmitting devices, and two fixed interconnections. The powertrain includes an engine and torque converter that is continuously connected to one of the planetary gear members and an output member that is continuously connected with another one of the planetary gear members. The six torque-transmitting devices provide interconnections between various gear members and the transmission housing, and are operated in combinations of three to establish at least ten forward speed ratios and one reverse speed ratio.