I have used a silicon spray from Gunk on the fuzzy part the window tracks on my 850. Aside form leaving a really nasty chemical smell it did a great job letting the window slide freely. I have also used it on the rubber door and trunk seals to help keep them from getting frozen shut in winter. If silicone spray does not work then try the litium grease on the window tracks behind the door panel.


Aaron

1997 850 n/a sedan
2001 V40 1.6T

No direct experience with the V40 but had a similar problem with our Miata. I used white lithium grease in a spray can with one of the plastic strays to spray grease into the window tracks inside the door. You can move the weather stip just enough to get the stray inside and into the track. Others had success on the Miata with removing the door panels and using silicone grease. The lithium method is not a perfect solution since you can only lubricate the top part of the track without removing the door panels, but it stopped the squeaking and it moves easily now. Don't spray grease on the windows or you will have a real clean up mess.