Nikon had previously replaced my 24-70 f2.8 AFS under warranty with a refurbished lens. In early January 2014, I contacted Nikon Service by phone as the lens had developed a noticeable squeak and grinding sound when zooming. I was told that since it was a refurb, it would not be covered under warranty. I explained that I did not buy the lens as a refurb but paid full price for a new lens and that lens had a 5 year warranty (which was due to expire in 2 weeks). I asked them to check their records, which I was told they did and they still said no.
A few weeks later, I mentioned the matter to a well-known Nikon guru under the theme of Nikon USA's lack of consistency with their responses to inquiries. I had been told at the time the refurb was issued that the remainder of my 5 year warranty would govern, or 6 months on the refurb warranty whichever was longer. After a few e-mails on his part, I was contacted by a high-ranking Nikon official who confirmed I was given erroneous information in Jan 2014 and the lens would be covered under warranty. I sent the lens in to repair and they fixed the problem at no cost to me. (wd)