WD5000AADS & AVDS drives in a RAID

I have a 3 disk RAID 5 on a storage machine.  There are two WD5000AVDS drives and one WD5000AADS drive.  The AADS keeps dropping offline.  I reubild it, it works for a week or two and goes offline again.  I have a replacement AADS drive to swap out but want to make sure the problem isn’t because of some obsucre difference between the slight difference in model numbers.  Any insight??

The thing is that this unit is not a Raid eidtion drive and does not have the TLER enable, please the WD article below:


the other thing is that even though wd is now saying you can use their desktop drives in raid, you can still only use them in raid 1 or 0.  also, those drives are different and you probably won’t get them to work in a raid together.