After 200 miles on the new car, I still have a clanking in the left rear going over rough pavement. I have changed the shocks and mounts all around (Bilsteins and URO front mounts and full upper replacement in the rear) and the rubber mounts for the rear exhaust. Much improved handling and quieter; major improvement in wind wander; and have encircled the parking brake cables with half inch rubber tubing that was banging against the articulated suspension. The indy says engine and tranny mounts are good. Not the spare or tools in the boot. Not the trunk lid, which banged around on my first X308 back in 02.

At eighty it is pretty tough to crawl under to look, and I think the suspension needs some articulation for the search to be useful, but I am willing to try. I could run it back to the indy, but he charges an arm and a leg and won't let me in the service bay to do my own eye balling . . .

Any suggestions?

 

There are about 5-6 different bushings in the left rear that could be making that such a sound (subframe bushings and LCA bushings). Additionally, it could be differential output end-play.
You could try getting the car up and then prying on various suspension joints with a long pry bar and looking for excessive compliance (not hard enough to break anything obviously, just a good tugging). Try prying on the subframe joints too.

Also, do a shake test where you rock the wheel side to side (looking for issues with bushings and wheel bearing) and in an out (looking for end-play).
There should be no movement possible side to side, it should feel solid.
As you move rock the wheel toward and away from the car, there should be only a little play. Compare the left and right sides.

Also, consider the specific timber of the sound. Is it more of a clank or clunk or rattle? Clank is usually metal on metal. Clunk is sometimes metal but other times rubber bushings or unsecured items. Rattle is usually unsecured items. Give everything that you can see back there a little shake to make sure it's secure. It's been a while since I've been under, but I recall there being some evap canisters and other boxes that might be culprits.

 

Here's some pictures so you can get an idea of where all the bushings are.
Also, when the shocks were changed, do you know if the rubber spring isolators in good condition?

 

The bolts that go through the orange colored bushings and into the body could’ve been accidentally left loose while replacing the rear shocks and upper mounts. Basically what he’s touched needs to be double checked to make sure all the fasteners are tight. I’ve made that mistake before when I’m in a hurry.

 

Thanks: definitely a clank. More and more convinced it is the parking brake cable, wrapping it with rubber hosing silenced much of the clanking, there is still some additional run that needs to be examined; but I need to get under the car . . . thanks for your thoughts. Spring isolators were replaced. Indy is sure it is not suspension or bushings . . . still, I need to check it out, personally.

 

Probably not the same noise, but my 01 XJR made a lot of racket when the rear suspension would articulate, speed bumps and such, less noticable on the freeway, but potholess, yes. I also noticed a groaning when I lifted the right rear wheel on a jack...figured out it was a u-joints on the two driveshafts were dry. Greased them up and it hasn't made any noise since. Probably not the same issue, but worth a check, they're really easy to forget/overlook.

 

Not my issue. One of the things I asked the indy to do was to grease those two Zerk fittings. Both of the two other 308s were never greased when serviced; once a dealer was surprised that they were there . . . Which, interestingly enough, they won't now work on any Jags older than ten years (too much Land Rover work probably) even though they had been servicing my latest for 17 years the previous owner owned it. OBTW, the indy said the zerks were dry . . .

 

It is difficult to even hazard a Quess toward a "clanking" sound we can't
personally hear or localize. However, to me, the word, "clank" would seem
to bring to mind a whole lot more indication of something heavier than a
brake cable.

The Duchess had a loose shock absorber that proved to be the problem
in my case.

 

As noted, I had to get underneath. When the fuel filter was changed a year ago, the mechanic failed to bolt the tie down clamp (or it vibrated loose); so the metal filter bangs (clanks) against the clamp over rough pavement. For a short fix, I used a water clamp to anchor the outbound fuel line to the return vapor line. Dead silent now. Next time I need to take it for service that puts it on a lift, I will have it bolted in correctly.

As noted: it truly sucks working under a car on jack stands when 80! But it is quiet, which for this OCD is worth it.

 

That is great you found the source. I know that had to be irritating.