Hi All, my 07 CL9 Euro started to produce some strange noise this afternoon. It looks like the noise is coming somewhere form the belt area and only appears when car is on gear (R, D), but not when car is on Park or Neutral (P,N). I did a bit of search and it seems like there could be few different reasons for this, like transmission failure, power steering pump failure or some auto tensioner.

Was wondering if someone with good knowledge can tell by the attached video what this could be and how costly will be repairing? Also, is it safe to continue driving or does it require urgent repair?

http://youtu.be/vLnagKMeIkM