I took apart my over/under on a 2-105 and had to wait days for parts to come  and now I have no clue as to witch way retainer clutch goes back in. One side has a lip while the other is flat. I am thinking that the lip side goes toward the rear of tractor but would like to know for sure?

 This adventure began with a oil soaked main clutch disk. I think the beginning of the issue was someone put hydro fluid in the main trans. Pulled engine and over/under. went to put new o-rings in and toke bolts out what I think is the direct drive portion trying to get to an o-ring, ended up cracking a disk in this section. Replaced bad disk, installed new o-rings. put engine and trans back in tractor only to not have direct drive. under drive and over drive but no direct drive. so it back in the floor. I can not see anything wrong inside, but when I set the pump cover down and got to looking could only find one of the small o-rings where there should have been two. It may have fell out while taking it apart and I did not notice. There is not much information available on rebuilding these.  Any information to rebuilding these would be great thanks.