I hate it when this happens
You are on the right track though. If the screws and nuts are free from pitch, cutting a lot of softwood will cause that, then the other issue would be the trunnions have some gunk collected. Blow them out, spray liberally with a solvent/cleaner, blow them dry then use a dry lube. It's been gradual so I don't suspect a mechanical malfunction, rather a build up of crud. I had the same thing happen to the tilt adjustment on a Craftsman 12" saw, but it was the screws that were gummed up. You should really run a dust collector full time if possible from under the saw base. Seal off as many of the big gaps as possible, the air will come in under the table and other places. Do not seal off the motor cooling hole...unless you always run the DC, it will overheat. I need to follow my own advice .....
The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)
Last edited by woodnthings; 12-26-2011 at 08:56 PM.