The family of transmissions has a plurality of members that can be utilized in powertrains to provide at least eight forward torque ratios and one reverse speed ratio. Further, the piezoelectric thin film is attached to the acoustic diaphragm in an inclined structure in which the piezoelectric thin film is horizontally turned from the acoustic diaphragm, thereby preventing a standing wave from being created by structural symmetry and minimizing sound distortion. The stored thermal parameter is read after the manufacturing activity and compared with an expected value to determine the status of the thermal subsystem.