US Patent 7311630 Multi-speed transmission with differential gear set and countershaft gearing

A transmission is provided having a differential gear set with three input torque-transmitting mechanisms, such as friction clutches, to achieve torque flow through the differential gear set to a countershaft gearing arrangement. The transmission utilizes power-on shifts. By utilizing the torque ratio of the differential gear set, additional forward ratios are available with good step progression, reducing the number of countershaft gear sets and synchronizers necessary in comparison to a dual-clutch transmission providing the same number of ratios. A shorter axial length is thus attainable.