I purchased a new washing machine recently and have had the problem of it overflowing the drain pipe I have read about new washing machines having stronger pumps which may be my problem .here is what I have though I have a 2" pvc drain line going from my washing machine directly to my main drian line as soon as the line goes under the floor there is a p-trap(is the trap necessary)it goes over about 2' and hits a Y and then to the main I have ran a snake through entire pipe and found nothing any ideas would be appreciated