SC mystery clunking noise

[Jvdv23]

I have posted about this issue before but I cannot find the cause for a clunking noise which seems to be coming from the right rear. It is not constant and it is not within the engine.

It sounds like the engine or transmission is somewhat loose and hitting the frame (exaggerated). I put the car on a lift and checked if I could simulate the noise by checking for loose parts but could not find the cause.

The engine and transmission mounts are renewed. The rubbers of the stabilizer are new. The mounts are not loose. The swaybar links are also renewed.

The noise arises when speed is slow and when accelerating or stopping but not always. I do not hear it when going over bumps.

Any thoughts on this issue to help me find the cause?

[timmy2]

CV joints checked?

[RDM]

What else is back there? CV joints, drive shaft, spring plate bushing, trailing arm bushing, and the bolts that hold them all together, perhaps?

[NYNick]

Put it on an alignment lift that lifts the car with all 4 wheels on the ramps. Get on the lift and push the car up and down to create the noise with someone underneath.

My bet is the sway bar.

[proporsche]

i think i have re: to you ..look at your hub caps, they could be loose. Not in the wheel .The cap is made with 2 pieces and those little nipples get loose and crate metal sound...the alu.face is loose on the metal part which is inserted into the rim.

Ivan

[75 911s]

My front clunk came from a loose gland nut on my strut insert. A rear clunk might be issues with the rear shock. Check the dust cap and fitment. You might even remove the side you think you hear it from, it's not that big of a job unless you have AC or a bunch of stuff blocking the top nut on the rear shock.

You might also try putting a camera / sound recording device in the general area of the perceived clunk and then do a short drive. If you can isolate the area it could really narrow the possibilities.

[manbridge 74]

Look around the rear shock too. Might help to have a guy grab the rain gutter and start rocking car side to side while you listen or have your hand on rear shock nut in engine compartment.

[Jvdv23]

I replaced the CV joints because they had wear marks. That did not fix the issue. I checked the trailerarm bushings and there is no play. I check for loose parts but nothing.

Any other thoughts? Could it be the torsion bars?

[theiceman]

take the torsion bar off and drive around the block.

.. you will know immediately if thats it.

[Bill Douglas]

Yes, I was also thinking torsion bar bush could be worn. Have a look and see if it is centered or hitting the top of the torsion bar end cover.

[wrxnofx]

Originally Posted by 75 911s

My front clunk came from a loose gland nut on my strut insert.

I had the exact same problem. Grab the strut bottom on the problem side and try and move it back and forth. If there is any play (there shouldn't be) that would probably be your clunk.

However, a common problem is for the swaybar bracket mounting point metal to rip. That would leave the swaybar clacking freely on the side where the mount broke. That would be my guess.

[walt]

I have been trying to track down a similar noise that I would describe as more of a knocking at idle, occurs only occasionally and at random, I to think it is external to the engine. Now you have given me a few more things to investigate. Please post what you find.