BMW E30 rear end whine and clunks
What causes whine from the rear of an E30?
Usually poor gear contact inside the differential, often due to loose differential bearings. The fix is new bearings and adjusting the clearances and gear contact. Worn gears do not always get better, so swapping in a sound differential may be the easier solution.
How do I tell whether the noise comes from the differential, the gearbox or a wheel bearing?
1. Remove the propeller shaft. 2. Turn the gearbox and the differential separately; the one that resists more is faulty. 3. Lift the car and turn the wheels by hand; a wheel bearing's noise changes with the direction of rotation. A dry rear wheel bearing can whine at speeds of 70-100 km/h.
What causes a clunk from the rear when pulling away and shifting?
Most commonly the propeller shaft's universal joint is loose or dried out, or the rear subframe bushings are worn. The car jerks when you lift off the throttle. Check the joints and bushings first.
Does an oil change help differential whine?
An oil change hardly removes the noise of an already worn differential, but the noise may quieten slightly. The noise can also come from the gearbox rather than the differential.