I have a 5005 and there is no "filter", just a screen on the return line from the resevoir to the pump. The return line is on the right side of the tranny. There is a split in the line (on mine anyway) right at the tranny so you can split the line, loosen the bolt on the resevoir just below the seat and remove the screen. Be careful when you put the line back together. I had a piece of the rubber peel off inside the line and stop it up. Cost me a hydraulic pump. You will want to drain it first (the plug is in the back below the check plug) or you will have a melluvahess.
Hope this helps