A hydrokinetic coupling has a primary vane wheel (11) and a secondary vane wheel (12), which define a toroidal working chamber. A shell (17) rotates with the primary vane wheel and envelops the secondary vane wheel. A constantly open and throttled outlet port (31) and an outlet valve (32) are disposed within the shell. The outlet valve can be closed by means of fluid pressure generated in a control line (33). In accordance with the invention, the control line has a fluid inlet (34) which is disposed in the shell interior. This is arranged at a determined distance from the axis of rotation of the coupling, so that fluid can only penetrate into the control line (33) if the slip in the coupling has assumed a specific minimum value. In this condition the outlet valve (32) is consequently closed, whereas it is opened at greater slip values.