Have a 2005 Five Hundred with 125,000 miles. Car starts and idles dead quiet, no grinding, buzzing, or other noise. No front end shake, no wheel chatter, but at certain speeds (30-60 mph) it starts a loud hum that sounds like the car is equipped with studded snow tires. Gets quite loud and eventually goes away above 65 mph or so. I'm thinking transmission but most forums I read indicate that transmission noise would occur at idle even, and that is not my case. Any other ideas? Definitely something in the driveline....

Thanks in advance.

 

I have the same noise, it gets louder when on a left curve and quieter on a right curve. I changed both passenger side bearings and no change at all. It starts at about 35 mph, but when slowing down, you can hear it all the way to stop. Does anyone know if the driveshaft rotates all the time or only when AWD is engaged?

 

This noise is driving the wife crazy, no one knows what it is? I am going to change the passenger front axle next.

 

Ok, I found out the noise, it was the left rear bearing. Even though it got louder turning left. Anyway, the new bearing didnt come with an encoder ring and the old one didnt fit the new bearing.