A torque transmission mechanism for an internal combustion engine, adapted to transmit a starting torque from a starter motor to a crankshaft of the internal combustion engine. A ring gear of the mechanism transmits the starting torque, and a one-way clutch (including an inner ring and an outer ring) disposed between the ring gear and the crankshaft. The ring gear comprises lubrication holes allowing lubricant to transfer from the internal combustion engine towards the one-way clutch. The torque transmission mechanism comprising at least one sealing element adapted to prevent lubricant from passing between an outer surface of the one-way clutch outer ring and a ring gear inner surface. The one-way clutch outer ring comprises a chamfered surface inclined with respect to a central axis of the mechanism and diverging respective to the central axis of the mechanism from the lubrication holes of the ring gear towards the sealing element.