Does it squeak or groan when you turn the wheels? If so, definitely the ball joint on the noisy side, usually the lower but can be the upper.

Otherwise, it's probably a bad track rod bushing (MB calls them guide rods) on the firewall end, probably clunks or groans on bumps on that side. Will eventually start to thump on going from drive to reverse as well, along with steering looseness.

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!