I have a 1990 300E 3.0 4 matic with 113,000 miles. Pretty much in excellent condition. I have noticed though a loud crunching noise coming from the right rear area, when going over a dip in the road.
If you have ever driven in snow, and had it accumulate in your wheel wells, and it crunches when the tire hits the snow or ice, this is what it sounds like.
The shocks, and springs seem to be fine. The car sits, and drives perfect. Could it be some kind of bushing or something?

Rear Sway bar?

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1989 300E 144K

Loose upper shock mount in the rear? Bad Constant Velocity Joint in the
rear axle?

Steve

Any quick ways to test what is? CV Joint test? sway bar?

The ball joint where the rear lower control arm connects to the axle carrier is the one that usually makes noise when going over bumps. Squirt a little WD-40 into the joint to quiet it temproarily. When repalcing it, do the left and right sides.

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1986 300E (3/2002) Rear ended and totaled (10/2009)
2000 Xterra (5/2000)
1992 400E (11/2009) -Sold
1986 300E (12/2009) - Sold
2004 E500 Wagon (6/2013) - Sold

Thanks