My Book Studio Edition II (2tb) major Problem

The drive lights up and mounts OK. The problem is when I open the drive, the are no accessible files yet it shows that I only have 163.7 gigs avail.

I attempted to run diagnostics with various programs with no success (unmountable, Drive not seen, etc.) Even though the icon shows up on my desk top.

I own  a MBSE II 1tb & 2tb so I’ve done the whole cable swapping thing and tried the same process on several Mac’s 

any idea?

When you say it shows up, does it show up in Disk Management?  If so, it’s possible that the drive was corrupted and the partition was damaged.  Be careful about pulling the drives to test them.  If you make any modification to them then the raid will have to be rebuilt; and if you need the data you will have to go to data recovery to retrieve it, if it can be retrieved.  If you still have the drive “as is,” then you might consider getting some partition/data recovery software and see if you can rebuild the partition.