Dear Mr. P.E.
Speaking only from experience with my '88 300E, I had a leak on the passenger side that was coming from a dried up O-ring way up on the side of the transmission. I believe my mechanic called it the secondary pump or something like that. Anyway if this is the problem, you have to lower the back end of the transmission to get to it. My leak only got worse.
2000 E55 AMG
1970 280 SEL (for sell cheap)
1959 Alfa Romeo Giulietta Spider Veloce