My M3 has 2,750 miles on it and I decided to treat it to a complete lube change etc.
Took out the bevel box drain plug and absolutely nothing came out I stuck my finger in to clear possible blockage and nothing but a finger covered in black light grease.
There has been suggestions of overlooking to fill these up at the factory, and others going through numerous flushing methods to get rid of the black stuff and feel with various types of heavy gear oil.
Years ago I had a 1948 or 49 Matchless and the transmission on that was 75% grease and 25% gear oil. The latter serving as a thinning agent to make sure the grease did not dry up.
I am wondering if this is also a similar situation. Once is supposed to top off with heavy gear oil and not try and replace. Mine took about 300 cc of oil without anything coming out in the first instance.
It would be good to know the real answer but in the meantime I am just going to let things be as they are.
