[jlkans]

My 2008 CTS AWD has developed a low frequency growling drive line noise most noticeable from 20 to 45 mph. Has 40000 miles on it and this problem has developed within the last 1000 miles. Is there a service bulletin that addresses this problem ? Getting ready to take it to the dealer and would like any information available that will assist them in correcting this problem.
Thanks in advance

 

[drw]

I've noticed mine is doing this too lately. I looked under the hood and while I'm not sure what the belt is, the belt which is front most on the engine is shaking a bit harder than it had been. This might be the cause of your noise.

 

[washide]

I've got what sounds to be a similar problem with my 2009 CTS AWD with about 36K miles on it. It may have been coincidence but the noise started after having the timing chain replaced. The dealer says it's normal "exhaust bog" and may be caused by the new timing in place after the chain was replaced. Whether that makes sense, I don't know...

 

[jlkans]

update, problem fixed, turned out being a bad wheel hub on right front.