Hi, if its still working then nothings broken. Sounds like the mechanism needs oiling, if you've got cables these rust and eventually snap(i've just fitted new cables to a Pug.)if you can spray wd40 into each end of the outer cable/sheath that should help alot.Go to the library & get a manual out for yours to see how the mechanism comes out, once the electrics are disconnected and the glass taken off from the slider it'll be easy to take out and check etc. Depends how big the access holes are in the inner door panel to see what needs doing.
Chris P.Duck, April 2010