I just did this test on mine, and all I hear is the power button. I place a finger on the power button and do the test, and no rattle at all.
does your auto-focus function properly? For this to work a lens is controlled by a magnet and moves ever-so-slightly when called upon to do so. When not in use, it just sits there and can move about freely. If it doesn't make ANY noise, I would wonder if it's able to move about freely enough to function properly.