US Patent 7670247 8-speed transmission

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