|I think, as Perry Mason would say, that you are "assuming facts not in evidence."|
It may just be that it's making normal sounds for the make and model drive. All drives make some noise as they move the heads, and some are louder than others. It may simply be that the way you have it mounted is sending more noise via the metal of the case.
Get ahold of the warrantee people and tell them your concern, see if they'll replace it. If another new one makes the same noise(s) then it's normal for that model.