Check the rubber bushings on the shock before replacing it -- they usually only need replacement if they are leaking. Knocks are loose bushings or a loose sway bar mount most often.

The struts are VERY expensive, but only usually fail when driven with bad accumulators long enough to blow the seals out.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!