Thanks. The car has 85000 miles on it. My first thought was that the hum was engine related, but the bodypart theory is interesting. It always seems to happen when the engine is at a low rpm for its gear. At 2300 rpm, especially when driving up a hill, the dark sound of the engine gets accompanied b...

This site is really wonderfull and has helped me quite a bit figuring out the 99 V70 XC I bought last spring. I have the following issue that I cannot put my finger on: When I accelerate I hear a low humming sound for a few seconds at approx. 2300 rpm between gear shifts (between 20 and 40 mph). I c...