Mine will grind into 2nd gear. It seems to get better, even go away, once things are nice and warmed up. I can get it to shift smoothly if I shift at the max shift points, or keep rpm's up while letting out the clutch. I plan on getting new/heavier oil in there as a first step...

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1982 240 D, 308,000 - 321,127 miles (sold)
1982 300 TD,166,500 - 226,000 miles
1998 E 320, 120,000 - 144,000 miles
2005 C 230 K, 26,000 - 77,000 miles (sold)