Abstract: A hydrokinetic torque converter mechanism for use in an automotive vehicle driveline comprising a bladed impeller, a bladed turbine and a bladed stator situated in toroidal fluid flow relationship, an impeller housing surrounding the bladed members, a lock-up clutch structure in said housing adapted to establish a direct connection between said impeller and said turbine, said turbine being connected to a turbine shaft that in turn is connected to torque input elements of a multiple ratio gear system, a one-way coupling located between said turbine shaft and said clutch structure for accommodating transfer of torque from said impeller to said turbine shaft but preventing torque transfer in the opposite direction thereby allowing coast braking of the driveline as the turbine tends to overrun the impeller but permitting direct mechanical torque transfer from the impeller to the turbine shaft during normal torque delivery, the driveability during coasting thereby being improved.