Optical drive HDD replacement

Hi guys Im have a late 2011 macbook pro 13"

Model Name: MacBook Pro

Model Identifier: MacBookPro8,1

Processor Name: Intel Core i5

Processor Speed: 2.4 GHz

My current setup is an SDD + HDD (Optical drive) setup

Im using my OCZ vertex 4 on my main drive and the stock hitachi HDD from apple in my optical drive

First issue I was transferring files on my SD card to my HDD media file folder when I accidentally pulled out the SD card the HDD was gone and left me with a question mark symbol

tried restarting and I gave up, the next day I was surprised that the HDD came back but it had a note on my disk utility

the HDD was red

"Drive has a hardware problem that cant be repaired" and on the bottom it said that the smart status is failing

So I decided to replace the hard drive with an WD blue

WD10JPVX So I reformatted the drive to mac osx ext journaled and putted it in a HDD enclosure so I used carbon copy cloner the transfer was successful

And then I decided to open up my mac and install the NEW HDD WD10JPVX in my optical drive now when I installed it it wont allow me to create folders or even access my iphoto library which is in the new HDD so decided to reformat and it wont allow to unmount so decided to take of the HDD again to do a reformat after that I installed it again in the optical drive with no files but it still wont allow me to create any folder or do anything with it

So I recently found out in forums that the macbook pro 13" optical drive only supports 3gb/s the one I bought was 6gb/s but some say the WD10JPVX is backwards compatible

so what might be the problem?

The old stock HDD in my optical drive is still working inside the HDD enclosure so decided to put it back inside my mac but I still got the message on disk utility "Drive has a hardware problem that cant be repaired"

Im using a generic optical drive HDD caddy

So what might be the problem? I cant return the WD HDD because of no return policy

My questions

1) Is it really backwards compatible WD10JPVX?

2) Is my caddy broken? how can I check?

3) If I would buy a new HDD what would you recommend?

4) Any trouble shoot so I can use the WD scropio blue WD10JPVX? (it has no jumper feature bat backwards compatible)