I suspect the driver's side lift angle is already broken. Stop using the sunroof until you can repair it or get it repaired, it's going to get stuck soon, probably partway open!

Lift angles are about $95 each, you will need both, probably some sliding pads (ridicoulously expensive), but if you keep going with it you will also probably bend the translation bridge when it sticks.

This is a DIY repair if you want to take the time -- do a search, I detailed what I did on the 300D last year.

Peter

__________________
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!