I recently bought a 2008 XC90 3.2 AWD. Everything seems okay except it makes a loud grinding noise when on low speed (below 20mph). No noise when I go on high speed. I changed break pads but it didn't stop the grinding noise.
Any one experienced this before and how was it fixed?

 

does it change pitch when turning left or right? since it seems to be road speed related, the likely causes are either a wheel bearing or an axle bearing/cv joint. Check if the axle boots are in good shape but my guess is its a wheel bearing.

 

I'm having the same or similar issue. It's not the brakes, axle shaft or a wheel bearing. Its a weird more rattling than grinding noise at low speed start off. goes away on the highway. Sounds like its coming from the mid to right front.