Abstract: A bypass drive line (27) for a torque converter type automatic transmission (11) in which the bypass drive line includes a viscous coupling (30). The viscous coupling is of a sandwich construction including an annular body member (32) formed of aluminum, an annular cover member (34) of steel secured at its outer periphery (34a) to the outer peripheral portion (32a) of the body member and radially inwardly thereof spaced axially from the body member to define a viscous fluid chamber therebetween, and an annular clutch member (36a) disposed in the chamber and having a central hub portion (36e) adapted to be drivingly connected to the output shaft (16) of the torque converter. Confronting portions (32e, 32f) and (36c, 36d) of the body and clutch members define closely spaced working area for viscously transmitting force from the body member to the clutch member.