I ended up getting a good deal on a NOS steering box for my 83 300D.
Not cheap, but it returned the steering to brand new quality.

I've never regretted buying the new box.

Of course, you also need to rebuild the front suspension, replace the column rag joint, idler, tie rods, and center link as well, to fully enjoy the new box.

Jim

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14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles