Well, even though it is freezing outside, I wanted to help my buddy Mike so I put on three coats, two pairs of gloves and a lot of long underwear. It was easy, just like you said. Two bolts and the cover was ready to come off. Mine was stuck so I had to pry it off. I was already to take photos to show Mike what he was missing. Prepare to be disappointed.
ALL I saw was OIL! Black, thick oil. If there was a filter in there - I couldn't see it!
Then I had a good idea. Use my camera's flash to light up the oil and maybe I could get a photo of something I could not see. It half worked. I can see a washer or something in there.