An end-of-fill detection arrangement is provided in a power distribution system to detect when a clutch is fully filled and the pressure therein can be progressively increased to full engagement. The arrangement includes placing a position sensor in a pressure relief valve that is controlling the desired pressure level to respective clutches and directing the sensed position of the valving element therein to an electronic controller. The controller monitors the position of the valving element in the relief valve. Initiation of filling of a clutch results in the valving element moving from a bypassing position towards a flow blocking position. This movement is noted by the controller and when the valving element returns generally to its initial location, the clutch is filled. The controller notes the end-of-fill and provides a command signal to the proportional valve to progressively increase the pressure in the clutch until the clutch is fully engaged. The subject invention provides a simple arrangement that detects the end-of-fill.