I have a 3 year old Nikon 70-200 2.8 VR and I sometimes use it with a Nikon 1.7 tele. This has happened twice now where the VR mechanism starts clicking when I go to focus. Not the normal click when the VR activates its a much more slower and longer click----click----click. It has only happened when the teleconverter is being used. I am thinking about sending it in for service. Has anyone had a similar issue?