This past weekend I did a complete oil change in my 426 for the first time (the dealer had done the first 2). I drained all the oil in the frame and the case and then I removed the oil filter. Well I take the filter cover off and find a bent up filter in the case. At first I wondered what was wrong with it and then on further inspection I found that the rubber seal that is on the inside of the case had come off so I get out my little dental tools and find that there was two of those seals stuck together and stuck to the back of the case. That is why the filter was all bent up and I would also venture a guess that the two seals stuck together like that would not make a proper seal. I took the valve cover off to see if there was any damage to anything and everything looked good. So I guess this is just a warning to check the (and you probably all do) outgoing oil filter to make sure it has both seals and if it doesn't to check the case to make sure there isn't anything left in there.