WD20EFRX "Clack"-Noise with noticeable movement

Hello all,

First off all, sorry if that question sounds odd, but I’d appreciate your help a lot.

I recently bought a DS216play with two 2TB WD Red (WD20EFRX). Unboxed, mounted, started. The whole “commissioning” just went fine, when suddenly after 20-30 minutes (the NAS OS was installed at this point and I started to transfer files) a repeating “Clack” noise every 15 to 30 seconds started. At the same time this noise comes, the hard drive shakes a bit. It is like something insite the HD wants to come out. Its not a very hard hit, but you definitely feel it. Its not the kind of movement I expect from a HD.

I took both of them (both of them make the same things) and took the to the store where I bought. they replaced them without any problem.

Now the new ones do the same. Exactly the same.

Slowly I start to feel stupid for hearing this, but I cannot imagine that the WD Red, which are so highly recommended and blessed for being so silent, are making this noise and movement.

Is there any other User who faced the same problem?

Short side info:
I do not own a PC where I can install them, because we only have notebooks.
I provided the DS216play with an own power supply, just to be sure the whole setup gets enough power (I start to hear the small Tim Taylor in me… MORE POWER).

EDIT: all four of them were packed in this “Bulk” packaging

Since every enclosure is different, some hard drives may appear to be noisier than tested or even appear to produce unexpected sounds.It’s possible for the enclosure’s acoustic design to be amplifying or highlighting the sound of the head-parking features of your WD Red drives.