Need help to diagnose a noise

[nysimonsez]

I have started to notice a noise coming from the front of the vehicle a couple of weeks ago. At first the noise is only present at high speeds (55+ mph), but it has become more regular and occur at lower speeds (30 mph). It is a low growl type of noise and gets louder and higher pitch (slightly higher pitch than engine noise when accelerating) at higher speeds. At 70+ mph the noise is quite noticeable, just a bit quieter than the engine noise under throttle. And the noise is present even if I let go of the accelerator, shift into neutral, or brake. The noise will become softer as the vehicle slows down and disappear when its below 30mph. Vehicle seems normal when driving at slow speeds or idling, at least I cannot hear the noise. I can think of a number of possible causes, what to get your thoughts on them (or any other areas I should look into):

- Wheel bearing – Not sure since I think the noise is there either I turn left or right.
- Differential/transfer case? I can shift into 2-hi or 4-hi without any problems, and the noise is there at those describe above in either case. I am going to do a diff fluid change anyway (+5k miles overdue) over the next couple of weeks.
- Transmission? I have a 04 v6 4wd with 120k miles. My main worry that the tranny is going. Is there some way I can check before having the mechanic take a look?
- Drive shafts? Last year, the passenger side CV boot clamp fell off and it took me a while to notice it but I did repack it with new grease. This noise was not present before or after I fix the boot.
- Tires? I don’t see anything physically wrong with them. They’ve got 40k miles on them with good tread left.

A couple of things I started to notice as well, not sure if it’s part of the cause or something else entirely. (1) Sometimes when the noise is present, I kind of can feel it thru the steering wheel and the pedals. It is a not a shake or shimmy, but feel more like buzzing. Also feels like something is rubbing (or metal grinding) against the steering wheel when I turn. (2) Seems like the tranny is struggling if I want to accelerate from 60 to +70mph, it’s like a fast pulsing noise (fub, fub, fub). When I let off the gas at +70mph, the noise is like a whirling sound and drops lower and quieter as the vehicle slows down (kind of like if you drive in D2 and let go of the gas at 40mph). This is where I worry it’s the tranny, but I do sense that the tranny is shifting to 4th gear, and not stuck in 3rd.

Sorry for the long description and I understand that it is difficult to determine the cause with just a description of the noise. I just want to get some ideas of probable causes where I can check myself before taking it to a mechanic, so I don’t blindly accept whatever he says, a case of fixing a,b,c when the problem is x. Appreciate any insight you can provide. Thanks.

 

[4gin007]

I had similar issues. I tracked it down to the wheel bearing. Installed a new one and the problem was solved. I have a 2005 with 103k miles. Hope this helps.

 

[superman3043]

I'm say wheel bearing or possibly stuck brake caliper. More or less just a guess though. Hope it helps. Good luck and report back when you actually diagnose it please.

 

[nysimonsez]

So I finally brought the car in for the mechanic over the weekend. He changed the diff fluids, spark plugs, and coolant flush (needed). I also asked him to diagnose the noise and to my surprise he couldn't find anything wrong. He said all the steering and suspension components are fine. The only thing he said is maybe a wheel bearing is going, but he couldn't tell which side, but said too early to worry about it. He said to wait till the noise gets worse or something fails (great, I wouldn't need him to tell me what the problem is then).

After I took the truck back, still having the same issues. One other thing I notice is that when going slow (5-10 mph) and turning the wheel about 3/4-full left turn, there's a slight vibration or shake (or maybe hesitation?) Hard to describe. Also, when I turn full clock right sometimes there's a high squeal noise. Not sure if either or both are related to my initial problem.

Last thing is I had a frozen caliper on front driver's side that I replaced last year. Not sure if the new reman'd caliper is the culprit, although brakes feel fine.

I'm going to bring it to tire shop and have them check the tires and balance. Then maybe find another shop to look into the noise further. Kind of annoyed that mechanic couldn't find the problem and I don't want to delay repair of any problems since this is my DD car.