Rear axle replacement requires removal of the rear differential; raise the rear of the car and remove the rear wheel, remove the center cap and reinstall the wheel, lower the vehicle to the ground, then use a suitable drift to release the staked side of the axle nut, with an assistant applying the brakes break free the staked collar nut at the center of the rear wheel hub without removing it completely, raise the car and remove the wheel, remove the rear differential and support left and right axle shafts with stiff wire, replace differential output shaft seals whenever axle shafts are removed; use BMW special tools 81 64 2 155 744, 81 64 2 155 745, 81 64 2 155 746 and 81 64 2 318 661 to remove the axle, and use the same toolset to install the axle using adapter 81 64 2 318 661 on the hydraulic unit with a torque wrench set to 20 Nm (15 ft-lb) to draw the driveshaft into the wheel hub until the torque is reached, noting that installation is the reverse of removal and that the sealing plate should be checked for damage and replaced if needed; replace snap ring (8) on the differential output flange shaft, install new output shaft seals on both sides of the differential and coat the output flange shaft (C) with differential oil where it contacts the shaft seal, position the differential with a suitable workshop jack, slide the left and right axle shafts into the differential and pull out the protection rings until they break away, push the output flanges fully into the differential until the flange splines engage and the snap ring audibly snaps into place, then complete the remainder of the installation in reverse order, install the differential per installation notes, and check the differential oil level.