BMW E36 driveshaft and rear subframe thump and vibration
Why does the E36 rear end thump or clunk when accelerating?
A common fault is the rear subframe mounting tearing out of the body; the tear can be seen from the underside of the rear of the car. Worn large rubber bushings of the subframe or loose bushings of the trailing arms can also be the cause. Check them first.
How do I check driveshaft play?
Put the gearbox in neutral (N), apply the handbrake and turn the driveshaft at the front end. If it moves a good quarter turn without the rear end rotating, there is play. The noise can come from the combined play of the driveshaft, the rear end and the drive axles. Also check the engine mounts, as they can cause the same rumble.
What should I know about the driveshaft flex disc and centre bearing?
Worn rear subframe rubbers let the angle of the rear end change under acceleration, which can break the flex disc. The tightening torque of the flex disc M12 bolts is 100 Nm (strength class 10.9) or 81 Nm (8.8). The centre bearing housing is pulled about 5 mm forward before tightening it to the body.