On my 92 240. Sound is coming from the rear of the car.

The best way to describe the sound is as if someone put marbles inside the tires. The strangest part is, it isn't speed dependent. It's the same at 20mph as it is at 2 mph. I can't hear it much above 20, but I think that's just due to wind/mechanical noise.

I can't replicate it by flexing the suspension while stationary and it still does it when the car is turned off.

I'm stumped.

 

I know some cars exhaust crackle and pop after driving them and getting the system hot.
But that is more towards the middle near the cats.

Could you possibly get a video of it?

 

Is this a new problem? When did it start and does it sound like a rattle. Does it do it at idle or only when the car is moving. Is your exhaust system sound and in tact and are the heat shields still attached. Are the rear shocks good and not leaking or broken. How about the brakes , when were they replaced . Next is the 2 piece drive shaft center bearing and the u joints. You need to determine if it is a rattle , bang , thump or some other type of noise.