Growling and humming from the rear
 

My first guess is another wheel bearing but I wanted to see if there is another possibility. The only reason I am wondering is the strange behavior of the noises. At 40ish MPH the sound is kind of a growling/moaning noise and is strongest when coasting down a hill. At 70ish MPH the noise is a high pitch hum. What is most strange is that the hum fades in and out on a regular period. It is almost like the beating you get when you pluck two strings of a guitar that are supposed to be the same note but are slightly off from each other.

So is the bearing still the #1 suspect or can it be something else?

Re: Growling and humming from the rear
 

if it's not your wheel bearing it could be your rear diff or your rear axle is out of balance.

Re: Growling and humming from the rear
 

Anyone else have any comments on this?

Re: Growling and humming from the rear
 

My open R160 4.444 rear diff is on its way out...... sound familiar :D

Tapani

Re: Growling and humming from the rear
 

I had a bad rear diff that was making noise that got louder with speed and it had a vibration that could be felt. When that happened I could distinguish that it was not a wheel bearing but I was not entirely sure.
I would have a shop check them on a lift, they can listen with a scope while someone brings it up to speed while on the lift. Should be quick for them to diagnose.

Re: Growling and humming from the rear
 

My RR bearing went recently. Sounded a lot like what you describe.
If you can get someone else to drive and sit in back you should be able to hear if its coming from one side or the other. Thats what I did anyhoo.
I'm guessing if it's the diff youd get an even tone sitting in the middle and a pleasant rumble in the jockeys.

Re: Growling and humming from the rear
 

Yeah, I am not getting any noticable vibrations. And it sounds like the noise is coming primarily from the right side but I could be wrong on that. There are other noises, like a faint very high pitched whistle or whine that seems centered but it is unrelated as far as I could tell.

Re: Growling and humming from the rear
 

Driving it on a lift and listening with a mechanic's stethoscope to the different possible points will narrow it down really quick.

The really bad wheel bearing on my blue car was actually enough to cause a wobbly/vibratey feeling. For a while I actually thought I had a bad axle because of it. But it was extremely bad, and had been bad for a very long time too:

https://lh3.googleusercontent.com/-U...0/IMG_0566.JPG

Re: Growling and humming from the rear
 

THE EVIL WHEEL BEARING RETURNS!!! KILL IT WITH FIRE.

Re: Growling and humming from the rear
 

Wheel bearing(s) gets my vote. I suppose rear differentials do fail, but consider the odds.

I noticed when I had a front wheel bearing going bad that the sound varied depending on how the suspension was loaded. Sometimes I couldn't hear it at all. Other times I just turned-up the stereo.

dcb

Re: Growling and humming from the rear
 

The mechanic agrees. I ordered a Timken bearing from autoparts123.com and will have it installed on Thursday. How easy is it to remove the sway bar bushings once the car is up on a lift? I am thinking of asking him to grease up the bushings and re-install them while he has the car up. The reason is that I read one person's experience of having their sway bar shift to one side and cause a rattling noise. Presumably it shifted and stuck.

Re: Growling and humming from the rear
 

Please have them check the hub. I'm replacing my bearing again after less than 10,000 miles because of a worn hub.:(
Gene

Re: Growling and humming from the rear
 

The sway bar bushings shouldn't be a big deal. Be sure they're not cracked. Oil-soaked front bushings should be replaced. Seems more likely that a rattle from a sway bar would be due to bearing deterioration. I know from experience that having one split apart and fall out results in an awful racket.

dcb