Been reading a bit about 'normal auto gearboxes' with a torque converter link between engine and gearbox, seems there is no clutch and the torque converter is still trying to drive the car even at tickover, but cannot put enough power through to move the car, as the revs rise the power transmitted goes up and if the brakes are off the car will move, but if the brakes are on and you increase the engine revs the converter will try to drive against the brakes, and the excess energy is lost as heat into the gearbox fluid. It seems that the torque converter never really removes drive power from the gearbox, and maybe the i-Shift has a torque converter which works like this, and has the ability to do a hill start because the system has devices to stop the car going backwards and will increase the revs to stop car rolling back. The fluid link between engine and gearbox means that when you put lever to 'park' position there is a mechanical lock applied to the output shaft of gearbox, which is why you should never select 'P' while car is still moving as this can shear the lock mechanism and/or damage the gearbox. It is recommended that with an auto box you should select neutral or park when standing still in traffic for longer times because it disconnects the torque converter, unloads the engine and the car uses less fuel.
