rear auto sunroof problem advise peeeese

My rear sunroof lectric has an annoying faault and i was wondering if anyone had any ideas, it opens on tilt halfway then you have to give it a gentle push to click it up the rest of the way then it doesnt open fully like the front, no whirring sound so no motor running, all electrics are fine as the thing opens a crack, i wanted to get in and service it, ie clean n vasaline so any ideas 'd be helpfull. 300 tdi ES

Andy

NEVER WORRY ALL FIXED, RUNNER LOOSE, Now all greased up n ready oh sunroof too!!!!!!!!!!!!!!!!!!!!!!!