500E, Rear suspension noise

[benzmark]

Does anyone have experience with a clunking or clicking noise in right rear suspension on my 93 500E? I have: changed sway bar link, air cell, hydropneumatic strut and tightened all fasteners. All bushings look fine as does the half shaft. This is a car with 44,00 miles, the noise is intermittent and occurs only under 40mph. I am told by a shop that looked at it for me when I was stuck for a better idea that it does not occur in reverse. Ideas? thanks, benzmark.