Thanks for the quick response jimmy57. My mechanic didn't mention anything about differential bearings being a possibility. He just proposed swapping out the assembly. Should I ask him to check that?

After having my 2005 xc90 misdiagnosed initially as rear wheel bearings needing replacement(and bearing that $700 cost) I am now told that problem is the rear differential needs replacement. I don't want to invest in a approximately $5,000 repair using a new part so I am considering replacing it ...