Strange isń it....
Message for dealer from MMC

" During the period between November 2012 until 9th September 2013 an additive was combined to the bevel box oil on all M3W’s. This additive over a period of time has been found to bond with the oil and forms clumps within the box, this can result in the gears not getting sufficient lubricant when required. It is essential that vehicles produced between these two dates have the bevel box oil changed, we recommend turning the rear wheel while filling with oil to flush any debris through the system (obviously as we recommend this is done at first service 1000 miles or 3 months whichever is first, all affected vehicles should now have passed through there dealer and the oil changed). "

You can always find than owners are capricious.