I had the exact same problem with my starboard side Crusader this afternoon. Never seen it before. Oil looks fine. It is slightly milky and dissapates
well it was just a thought that i have a short shaft merc and wanted to fit mid section from my 40 merc to it i will have a look at the serial numbers
I will post some pictures of the inside parts for you to see.
If you happen to read my reply back before I before I get out tomorrow
by the way I have also installed a new tach it is working properly still no charging
reminder if hole I think it can travel down drive shaft or shift rod so don't rule out shift shaft seal or somewhere up top..use flash light after use