I did some further investigation with my friend google on your strange disk problem.
My assumption is that there are much more users that have a WD drive in their mede8er without having the same problems.
A summary of all the root causes that could give you this kind of behaviour:
1] a problem with the sata handshake between mede8er and WD disk
2] a connection problem
3] a HW problem
I would advise the following approach regarding to get to the root cause of your problem (and in this order):
1] please check your WD drive jumper settings.http://wdc.custhelp.com/cgi-bin/wdc.cfg/php/enduser/std_adp.php?p_faqid=1271
or find your drive here for correct jumper settings: http://support.wdc.com/product/download.asp?level1=6&lang=en
The drive should be jumpered as default, so no jumbers placed. (no PUIS mode, SSC disabled, OPT1 disabled)
2] check your Sata and power cabling in the mede8er box:
- are the cables firmly seated
- check on cable damage of both power and sata. Verify that it is not running over the metal cool block on the cpu of the mede8er. This get's hot and can damage your cable
3] if above is not helping then I think you have some kind of HW problem, like:
- a defective disk that is not spinning up now and then
- a power problem on you mede8er not feeding your disk correctly resulting in spinning problems or other kind
- a defect on the SATA driver chips on your mede8er
Try to place another disk if you have one to verify if it is a defect on disk or mede8er.
But as far I could read you already tried that.
When all attempts above are failing then I would advise to contact your mede8er reseller to get it fixed or swapped.
Hope this helps to get your problem fixed to become a happy mede8er again.