No luck with the previous suggestions. I believe the e-ring that "shot out" on reassembly was #54 on this diagram. It was shiny clean like fresh water kept it looking new and not inside an assembly...
I made the tragic mistake of not aligning the shift rod before installing lower unit. When tightening it up, I heard a "ping" and a shiny e-clip flew out. I believe it came from the shift rod that goes into the lower unit. Now, it won't shift into F or R. This is after I got it aligned properly...