When from the coupling phase, the returning fluid will reverse path and now rotate while in the way of the impeller and turbine, an effect which can attempt to forward-rotate the stator. At this point, the stator clutch will launch as well as impeller, turbine and stator will all (roughly) https://elliotnwacc.thelateblog.com/34747799/detailed-notes-on-torque-converter-clutch