The truck I am working on is a M923A2......
Plode, I took the small one back off and the little o-ring had remained on where the filter screws onto. I should have known better than to not look. Now back to the big filter, obviously the old filter was in backwards, put it in handle up, which makes sense since the large attached o-ring will sit nicely on the metal spring loaded plate in bottom of the housing. On the big filter, it came with a small o-ring....no idea where it goes. I don't see a place for it at all. Thank you! Will be back home to where I can easily look at my TM'S tomorrow.