washer drain problems

i am having an overflow probelm with my washer drain. it is a slow overflow in that you cant hear it running down the walls and spilling onto the floor. i took off the drain hose and looked down the drain pipe with a mirror and flash light and saw something that looked like the bottom of a small can in the pipe.tried to rin a snake down the pipe but cant get past this object. is it a suds reducer? or an over flow reducer ? or is it supposed to be there? my washer drian is in line with my kitchen sink and i dont get any back up of water in my sink. i also ran a snake through the sink. the over flow has gotten so bad , ihave to replace the sheet rock on the walls.thanks for your help. Ron