My sunroof in my 240D has a similar problem. It will open, but not close fully. It makes a clicking sound like a gear slipping when it gets stuck. Using the manual tools causes the same noise. I removed the motor from the gear box and removed the plate that covers the gear box, but all of the metal gears in the gearbox look fine. Is there a plastic gear elsewhere in the system? How do you remove the gear box from the cable? Can the teeth on the cable strip out easily? Thank you.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine