I have heard it on Zeus (I think it was, or maybe Kermit) drives before, quiet tick(s) when power applied and it's been down to the heads assembly.
Had one case a while ago from New Zealand where a raid server had a power surge and it cooked all preamps (or shorted something in the heads assembly, I didn't care which, all I was interested in getting the data!) causing none to spin up, just made ticking noises. Changed heads assembly in all 4 drives (using one set of donor heads for all 4 as I remember) and recovered data in full.
But yes, agree. Check the motor by blocking the heads from the PCB with card or whatever.
As data-medics says, I have never seen a bad (as opposed to siezed) motor in a modern WD drive but not saying it doesn't happen.
Closest I remember was a Hawk drive that had somehow got the motor wires shorted underneath (under the glue) and it was making some strange noises. I picked away the glue and separated the offending wires and all was good

_________________
PC Image Data Recovery
http://www.pcimage.co.ukNew!! HDD-PCB.COM for all your PCB and donor HDD requirements!