Remove the exhaust system and disconnect the rear driveshaft from the differential and support it; remove retaining cover and nut (8) with seal, always replacing the retaining cover and insert nut at the rear differential with new ones; mark the position of flange nut to the differential pinion (8) and reinstall the nut in the exact position later, avoiding tightening beyond its original position to prevent internal differential service; using BMW special tools or an equivalent flange holding tool, loosen the flange nut and note the number of turns to fully release it; use BMW special tool 00 5 010 or an equivalent seal removal tool to remove the seal from the differential housing, then use BMW special tools 00 5 500 and 33 3 470 or equivalents to drive the new seal into place until fully seated and remove all remnants of grease and thread lock from the pinion threads; pack the collar insert of flange nut with grease and apply a thin coat of grease to the shaded area of the flange nut, coat at least four threads of the flange nut with DAEi BOND type 1385 or equivalent, install the drive flange on the pinion shaft and install the flange nut, tightening it to the matching marks made earlier and not beyond those marked points to avoid replacing the clamping sleeve inside the differential housing; place new nut with seal onto the flange nut and install retaining cover, do not use the flange nut to counterhold the driveshaft as this may damage the rear differential; complete installation by reversing removal and install the driveshaft to the differential.