My wifes car is a 04 xc70 with 135,000 miles on it, we had a whine that first sounded like the tires,rotated them and it got worst,after afew weeks it got to the point where the whine changed, when you gave it the gas and coasting, I changed the right front cv axle, the axle was dry and tinny sounding and the bearing was hard to turn,took it for a ride and the whine changed, took it back to my shop and looked under the car and found the drive shaft would move about a quarter of an inch, the bevel gear pinion bearing was gone,replaced the bevel gear and when I was putting the drive shaft back in the front cv on the driveshaft fell apart and a ball bearing fell out, ordered a new cv from colordo driveshaft and got back in ,now the car runs like new,, that was the short story.