All of a sudden I have a loud humming noise that seems to get louder as I accelerate. At first I thought it was tire noise, but it isn't. It seems to be coming from the rear of the vehicle. It is really annoying at high speeds. Has anyone else had this occur, and if so, what did it turn out to be?
It's a 2007 2.4 LT.

 

You did look under the car for captured grocery bags etc.? It is not the "open rear window,closed front window" thing? Door gaskets, door not fully closed? Remote possibilities; Fuel pump, wheel covers, wheel bearings? I'm out.

 

my guess is you have a bad wheel bearing

 

Well first check the obvious things, stick your head under the back end to see if you've picked up something off the road, then look for anything that might be jarred loose. I once had a tremendous noise coming from underneath that turned out to be a plastic bag wrapped around the axle, sounds stupid but it gave me a serious "what the hell is that?!" moment.

Also check the exhaust, it might be loose in its rear hanger and vibrating up against the under body. Probably the biggest thing to check though is the rear wheel bearings, if you don't find anything else, jack it up safely and spin the rear wheels listening for bearing noise. Or have it checked out by your dealer/mechanic.

 

I agree with all that has been suggested so far...... Wondering how you ruled out tire noise though. You may want to rotate tires and see if there's any change..... Unless you already did that.

 

x2...

 

Dear DrummerHHR,

I read through your post about the humming noise that you are experiencing as of this past Friday. How are things going with this? Did you decide to look for the suspects that the members of the forum recommended or did you make an appointment with the dealership?

Sincerely,
Michelle, Chevrolet Customer Service

 

If it is not a tire, most likely a hub bearing. If you are under 100K it's covered for free by power train warranty.