My washing machine leaks during the drain cycle, but the origin of the leak is not visible. I've already pulled the front panel, but no leak is evident. the pump is working fine and the wall frain appears to be clear. each time it drains you can hear the water go down the wall drain, but the is approx. 1-2 gallons of water in the tray. I cannot see any visible leaks at the tub, the pump or the drain lines. Could the machine drain line be slightly restricted enough to cause the leakage.

I've already pulled the front cover and ran the washer through it's drain cycles at least ten times. Each time the the pump comes on there is 1-3 gallons of water in the tray and nothing inside the washer shows any signs of leakage. I've checked everything inside the case while it is running, which included the pump drain lines, tub...and still there appears to be no origin for the leak.