P:roblem Nikon AF lenses.
Have to say I'm rapidly getting disillusioned with autofocus Nikon lenses, not the optical quality which is excellent, but the "plasticky" materials from which they are constructed, which seems to give them a vulnerability to damage, from the odd knock to inclement weather conditions. My 28-105mm developed "wonky barrel syndrome" after several months use, now my 35mm f2 has developed "sticking diaphragm blades" for the second time, having been "cured" of the same fault by Nikon only a year ago.
My older all metal Nikon manual focus lenses have never given any kind of mechanical problem despite extensive use in all weather conditions. As an independent repairman once commented on taking apart my 28-105mm AFD lens. "If folk could only see the flimsiness of materials used on the inside of this autofocus stuff, they'd never spend good money on it.