One bolt. Cover plate drops off the bottom and the filter comes out with it. Careful with the perimeter o-ring in the cover plate. Careful with the vertical orientation of the filter and its attached spring. IIRC, the sump has TWO drain plugs; one forward, one aft. Remove both for a complete drain. Be VERY careful reinstalling the drain plugs. Quite easy to strip out those aluminum threads. Doesn't take much torque.
Patrick Hayes
Fremont CA