BMW Z3 clunks or thumps when shifting
Z3 clunks when shifting - what causes it?
The most common explanation is that the clutch does not fully disengage before the shift and the gearbox gears hit each other. The noise is often heard at low speeds. A clunk, for example from second to third, is fairly common in the Z3 and is usually not serious.
How can you locate the source of a Z3 thump?
Put the car in neutral with the handbrake on, then rock the car back and forth by the rear wheels. If the same rattle is heard, the cause is probably in the rubber bushings of the rear subframe. The rear should not move at all, so any movement points to worn bushings.
What other causes of Z3 thumping are there?
Replacing the bushings does not always remove the noise, so the fault may be elsewhere. More serious causes are a broken gearbox mount or a torn rear mount. In the Z3M the cause may be a loose dual-mass flywheel or worn rear bearings.