My 2.7 TDV6 has an annoying (to me ) rattle or clonk from the rear when I go over potholes. It doesn't always happen, only on certain ones. It's fine over slow speed humps.
I thought it was the rear hatch and have tried packing the lock, but that had no effect. I've just had a look underneath, and the exhaust doesn't make any noise if i wobble it. The only thing I could find that would make the noise are the big metal harmonic(?) dampers that hang from the very rear of the body. If I move them, they clonk on some thing that I can't see.

Has anyone noticed this and or found a fix for it ?

Cheers

I think I tied pipe insulation to the dampers. To stop this.

Also check propshaft center bearing

(Just in case anyone else has this), it's definitely the harmonic dampers (two big metal weights under the rear body, between the spare wheel and the bumper. I think it must be that the rubber bushes that they hang on have aged, and allow too much movement, so they hit either the bumper or a metal bracket on the underside of the boot floor.
I have wrapped some foam insulation around a bolt in front of the weights, then tie wrapped them to this bolt. I think they need several tie wraps, or they work loose. as they are quite heavy.

Stopping the harmonic dampers swinging about so much has had a strange effect on the RRS. It seems much nicer to drive, with a noticeable reduction in vibrations from the rear when driving over rough surfaces, potholes etc.

Thinking about it, I suspect that the rubber bushes that hold the weights have aged and now allow too much movement, hence them "clonking" on the body/bumper. But it also means that the damper is not as effective at reducing the vibrations of the body over bumpy surfaces. At first I thought I was imagining it, but now I'm sure it has improved the ride.

I might think about trying to fit new bushes, if it's possible.

I think I've heard an occasional clonk from the back .. must crawl under there and have a look for these, what I now imagine to look like, Range Rover Testicles..  2014 BMW 530d Touring, 2006 BMW 650i, 2018 Mini Cooper S