Disk depend

I have a win 2008 sql 2008 active passive cluster. All of a sudden could not add new staging database told me d drive not available. Currently can query active databases on that server, I can edit a notepad file on the drive, but can't create any object backup\db to the box. Go to cluster admin and look at sql resource and D drive not listed as a dependency. I am guessing it flaked out, anyone seen something like this before? Going to add back tomorrow and flip to other node and hope it comes back. Right now if it fails without this main data drive I am dead in the water