I agree with old turkey. There are a few different ZIF cables used in the iPod Video and Classic, and for the most part all of them are interchangeable without any consequence. The only exception is one particular hard drive for the Classic that slips my mind, but it uses a very unique cable and that cable won't even properly fit in the other drives.
I would say to see if you can get your iPod into diagnostics mode and then go to IO > HARD DRIVE > HD SMART DATA and see how many reallocs and pendings you have. This test refers to the sectors, and you want to hope for a 0 result for each. The higher the number, the more damaged or bad sectors you have.