hey I have a 2000 scrambler 500 4x4 and it started making a thump sound when it is in neutral its like something is bumping the plastic transmission cover every roation. When you put it in gear it quits. I ahve not pulled the cover yet but was wondering if anyone has ever had this problem or what should I look for.

 

Your clutch or belt could be rubbing on the clutch cover. The cover gets warped from the heat overtime and can sag. You may need a new cover and backing plate.