[CaptainHaplo]

Question - is the drive set in a raid array of any type? If your not hearing the dreaded clicks I wouldn't sweat the drive too much itself.

A HD has no internal mechanism that can create a beep on its own. If its in a raid array then check the raid controller (as they usually have an audible alarm circuit of some type). Doublecheck the heat in your box, you may be getting a temp alert or something similiar.

When in doubt, double check your backups and insure you are up to date just in case.

If you want to find the issue, open the box, disconnect all unneeded devices, etc and run the box. Trace the sound by ear as needed. If opening the box keeps the sound from occuring - you have a heat issue.