150baker, I responded to your other post with what I know. I will add here, though, that I didn't add any oil when I put it back together, because as you said the manual is silent. It is a curiosity why it has fill and drain holes. Maybe it had something to do with running the front end under water in the rice paddies of it native country. It certainly wouldn't hurt to add oil since the seal leaks through a little anyway. I used UDT oil in all of the other reservoirs.