We have already replaced the angle gear and the rear wheel hubs per Volvo. The same sound persists and Volvo Oak Park (Chicago area) does not know what it is. I would also check the fluid level in the gear since they are known to leak. I am currently getting a grinding/rumbling sound when coasting which may also have something to do with the angle gear so I am replacing the entire front suspension tomorrow in hopes of eliminating the sound without having to replace the gear. I do know that when I replaced the strut inserts, the right front knuckle dropped pretty hard while the left front knuckle stayed in place for the most part. So I may have a bad CV joint on the right side. I will let you know what happens. Anthony