JOHN STEPHENS

Ok, I have a 2004 CTSV with 62,000 miles. When there is a rapid change of power and when I let of the gas and get back on it there is a clunk in the rear. Also it seems like when I turn it binds sometime. And slight whine in a few gears. I was wondering if I would be better off just replacing the whole rear end? Or what should I replace? And from who should I get the parts?

Thanks guys!