BMW E32 driveshaft vibration, clunking and leak
Why does my E32 driveshaft vibrate or clunk when accelerating?
The most common cause is a worn centre bearing or its rubber, which has stretched or shifted off-centre. Also check the driveshaft support bearings, the play and binding of the universal joint, and the dust covers of the flex joint and the differential. The support bearings wear, so check the play regularly.
What can cause a clunk in the E32 when changing gear?
The noise can come from anywhere in the drivetrain. First look at the driveshaft support bearing, the universal joint and the differential dust covers. A worn dual-mass flywheel or a poor clutch disc can also rattle, and a broken rear exhaust silencer can thump underneath.
Where does the oil leaking from under the E32 driveshaft flange come from?
The leak usually comes from the flange's shaft seal (50X80X9, part number 33121213949), and it is worth replacing the drive shaft seals at the same time. Mark the position of the flange nut before opening it, because it affects the bearing clearances. A blocked breather hole in the rear cover can also cause leaks.