Correct diagnosis is they key. How many miles in your car?
In my 1983 E23 735i 5spd, the Rear Main Seal leaks at 130K, the FRONT Man Trans Seal leaked at 140K miles.
I suspect you have man trans oil seals leak.
Wipe the whole area dry, drive a short while and look again. The problem is: the engine oil and man trans oils look very similar and almost impossible to tell the difference.
(In contrast, if one has an AUTO trans, then the auto trans fluid usually has a red dye that can tell you it is ATF).
Google for "engine oil dye", I think there is a dye you can put in engine oil to trace leaks.
The dealer should have changed ALL 4 seals in the man trans when it was removed from the car for the RMS leak.