Been there too. If it's not what 240DieselDog says, then check the gears. They're held in by rivets and they will break in time. I have one repaired by a bolt with real thin head and nut that I ground from a normal bolt and nut, another repaired by putting a steel rivet in. Both methods are working for me, so far.

The door panel has one clip at about a 45deg angle toward the front. The rest point down. When you get the junk off the door panel, the panel comes off by lifting (gently) then pulling up and back to get that 45deg clip loose.

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daBenz - 1970 220D