Joel J , May 31, 2012; 01:18 p.m.
Not that it helps solve your problem, which sounds like something needing adjustment inside your lens, but there is no 70- 200 DX lens, nor is there a 70-200 Nikon lens with an aperture ring.
There are 70-210 lenses with aperture rings, and there are 70-300, 75-300 and other assorted focal length ranges. Just no 70-200 non "G" lenses nor DX lenses.
Something that I find very useful in communicating to others, and just keeping track of what lens is what is this website:
Not only is there lots of good information regarding when made, serial numbers, etc., but if you click the link for each lens it takes you to an image of the lens in question.