Regularly comments are made regarding a lack of clutch in the HSD but a youtube video from Western State University shows a clutch and pressure plate attached to the shaft driving the planetary gear carrier. Although this is apparently a second generation HSD it prompts several questions. 1) Does it still exist in the 2010 Prius HSD? 2) Does it engage and dis-engage every time the ICE is started and stopped? 3) What engages the mechanism? Electric or hydraulic? You see, I'm trying to figure out what happens to the ICE when it is OFF. Is it continuously turning and driving the pistons? If so are the valves fully opened? Maybe not necessary if this clutch is disengaging. Thanks for the insight.