Klaus may be correct, but before you return this part, make sure that this was not something that you did to cause the problem.

CV joints, when new, ARE tight.

As to whether or not you know there is grease in the joint, I'm not so sure you can tell.

See if you can get that sound file working so we have a better idea of what your problem is.

There are a dozen reasons that a new sound could have cropped-up. For instance, you could have accidentally bent the backing plate and it is now rubbing against the disk rotor.

So, before you bother FCP with something that may be your issue, double-check your work.