window winder trouble

[sonoramicommando]

So trouble comes in threes, just when I put the car on the market - first the windscreen crack, second flooding of the cabin, now driver's side window winder is reluctant to raise (and to a lesser extent, lower) the glass. When turning the winder, it feels like it's failing to catch on teeth and spin. If I turn very slowly and carefully, it does move ok, albeit with some resistance.
Is this common issue? Is the winder mechanism easy to replace?
Any pointers would be much appreciated.

[Stonehopper]

Mostly the glass becomes unstuck from one or both of the two carriers, and can fall down into the door cavity. I have this issue with two of my doors (also on Ami 8 doors in the past). Never had issues with the actual winding mechanism though. Access is restricted due to the apertures behind the door panel. Could be that the fixings for the mechanism to the inner door panel have come loose.

[sonoramicommando]

Thanks - Wish I didn't have the manual remote control mirror, it would be far easier.