I have a similar problem with the sunroof in my 88 300 SE. I tried to use the hand crank and carefully move it back into the roof and the latch or guide snapped off and jammed in the slide mechanism. Now, of course, the sunroof cannot be used. I think I will have to remove the headliner to get at the problem.
Can the sliding roof be removed without taking out the headliner, that is by pushing it up from inside the car and undoing or unscrewing something so it can be removed?? Does anyone know?? Thanks Lee