Occasionally my 6 year old Kenmore 70 Series washer will drain water while filling during the wash cycle. I usually notice this about 1/2 hour later when the water is still running into the tub, the tub is only half full and the timer is still on the wash cycle. If I am lucky, it will have filled faster than drained and I can adjust the water level low enough to start the agitator which has always stopped the drain process. I then reset the water level and continue filling. If there isn't enough water in the tub to do that, the other thing that has worked is to change to a rinse cycle and start filling. Once the draining stops, I've always been able to go back to the wash cycle and continue filling. What could be causing this. This happens about one of 10 loads.