Have a dishwasher, Kenmore Quiet Guard 2 (Model 665.15992400). It came in the house we bought, and needs cleaned badly. I can't seem to remove the filter at the bottom, I've removed the sprayer arm assembly and everything down to the piece that turns the arm (http://imgur.com/a/7Vy3Q) it looks like someone mauled on that before a little with a wrench or pliers. Am I going at this the wrong way? Does anyone know how to get that piece out to clean? There is visible gunk down in there.

The part I am trying to remove says Assembly No. 9742968. All of the manuals I find when searching for the model number appear to be for the wrong washer.

Anyone have any suggestions?