2007 X3 2.0d E83. Had to have the rear drive axles replaced as the reluctor rings were corroded. Work done by BMW Dealer. After driving for a few hundred miles, I happened to look under the car and there was oil from the right side of the differential splattered over the underside of the vehicle. Took it back to the Dealer. They said that the retaining spring for the drive flange was old/weak, resulting in it pulling out from the differential, and charged me £150 for replacing spring and oil seal. About a hundred miles later, nasty rumbling noises in car. Took it to an independent garage. They showed me that both flanges had pulled out of the differential with loss of oil etc. Car towed back to the BMW Dealer. After discussions with headquarters, the Dealer replaced both drive axles, drive flanges, retaining springs and oil seals under warranty. A hundred or so miles more and- you guessed it- both flanges pulled out of the differential again. BMW Dealer is adamant that the drive axles are the correct ones for the car, but I am becoming sceptical; there are several different lengths of drive shaft indicated by OEM parts suppliers for a mid 2007 X3 2.0d E83. Any ideas?