Buzzing noise from front end


jwardl
06-05-2006, 06:55 AM
One day on the way home from work, my car developed this peculiar buzzing noise. The noise increases in pitch and volume as the car goes faster, and sounds rather like the propeller noise on a turboprop airplane. The car also vibrates -- not severely, but enough to notice.

The car drives fine aside from this. I've checked the transmission fluid, and it looks ok. No sticking issues that I can feel or see via the tach. I also tried shifting into neutral while moving, and the noise wasn't affected. I do, however, get a quick (less than a second) "slip" 2-3 times a day, always while accelerating.

I've noticed that when turning RIGHT, the noise disappears during the turn, but persists at the same level when driving straight or turning left.

There are only a few other issues that *might* be related:

1) When decelerating, I can hear a ticking noise coming from the right side, somewhat like the sound of a playing card in the spokes of a bicycle wheel. Haven't noticed if it's affected by turning. CV axle?
2) For a few years now, have noticed a repetitive squeak when driving. It's noticeable at slow speeds, but I'm certain it there always -- just drowned out at higher speeds. Sounds like it's from the front passenger wheel. Hub?

Just had four-wheel strut rep/alignment. No change to any of these issues. Also replaced brake pads/rotors recently.

Oh yeah: 2000 GP GTP w/sc, 146k, auto trans.

BNaylor
06-05-2006, 07:36 AM
The ticking and airplane like sound is a bad hub/bearing assembly. A bad bearing will change pitch from low to higher speeds. Also, while cruising and going straight you can change the pitch and even lose the sound in certain instances when rocking the steering back and forth.

jwardl
06-05-2006, 08:48 AM
...and that would account for the vibration too, right?
What about the squeaking?

BTW: Edited the message; the previous point#1 about the whining *was* the power steering pump. Added fluid, problem solved.

BNaylor
06-05-2006, 09:13 AM
...and that would account for the vibration too, right?
What about the squeaking?

BTW: Edited the message; the previous point#1 about the whining *was* the power steering pump. Added fluid, problem solved.

The last bad bearing I had I could feel vibration but the worse part was the droning airplane sound. Gave me a headache. Is the squeaking there at all times even with the brakes applied? Is the noise all on one side or both?

jwardl
06-05-2006, 09:28 AM
The vibration is obvious when carrying anything that moves easily: open drinks, plants, etc. One can easily see them shaking.

The squeak is only when the car is in motion, and sounds like it's coming from the front passenger wheel. That particular sound has been around for a couple of years, and is repetitive. I can hear it with the windows down and AC off to keep the extraneous noise down. The faster I go, the faster the squeak. It stops eventually as I speed up, but as mentioned before, I think it's just that the extraneous noise overrides it -- and probably that the repetition blends into one long tone as I accelerate.

richtazz
06-05-2006, 10:09 AM
I agree with Bnaylor, it sounds like a bad hub bearing to me.

jwardl
08-05-2006, 10:35 AM
Replaced the left front hub bearing (where the vibration and sound seeme to be coming from) -- NADA, no change. At least now I know how to change a hub bearing. Maybe a different hub is bad, which would account for the previously mentioned squeaking/ticking (which is coming from the RIGHT side).

The vibration seems to be centered right under my feet while driving. It now grinds/growls even when turning right, albeit, less. It also is reduced momentarily when descending from the peak of a bump.

I can feel a high-frequency vibration when touching the shifter, but my impression is that the vibration is coming THROUGH the transmission rather than from it. Again, aside from the ocassional quick slips, shifting and power are fine.

Any chance this could be the CV/half-shaft or the gear that drives it?

BTW: I've since changed the transmission fluid/filter. No unusual wear noted, but no change to this condition.

BNaylor
08-05-2006, 10:56 AM
Bearing noise is deceptive. It could be the opposing hub/bearing. I had a similar situation but the sound was a distinct humming noise that varied with speed. After installing the new hub (right side) the noise was still there so I installed the one I removed on the left side and the noise disappeared. I don't put much mileage on the GTP or use it for street so it was no big deal re-using my old hub.

The CV joints normally do not make a humming/buzzing sound. More like a clunk or metallic ticking sound. But they can cause vibration. I recall GM had installed some flaky axle half shafts on some 2000 - 2001 model Grand Prixs so might be worth looking into to.

The part that drives the axle half shafts is the differential located on the passenger side of the transaxle. Also, there are output bearings/bushings on each side of where the half shafts go into the tranny which could generate noise.

jwardl
08-16-2006, 11:36 PM
It *was* the opposing hub/bearing. I replaced the right side unit with the old one from the left side. Not proper, perhaps -- but le$$.

Sure is nice to have that sound GONE, and with relative ease. Of course, I
cross-threaded the top caliper bolt when putting it back on and can now only turn it a few times before it stops -- but I suppose that's what tap/die kits are for :)

So, given my experience, I'd suggest this to anyone with this buzzing... if turning the wheel in a certain direction reduces or eliminates the noise, replace the hub/bearing on the side you turn toward.

corning_d3
08-17-2006, 01:05 AM
Better get that caliper fixed. I had my top caliper mount bolt back out n the caliper lodged inside the rim and locked it up at freeway speed. Ruined the rim, and flat-spotted a $200 tire also. How come you didn't replace the right side first? Didn't you say that's where the noise was coming from?

jwardl
08-17-2006, 03:22 AM
Wow...

Well, some squeaking was coming from the right side, but the droning airplane-type sound was coming from the LEFT (under my feet) -- seemingly, at least. Also, the clicking noise I could hear sounded as if it was coming from the right REAR. That all said, ALL the noise was eliminated by replacing the front right hub. I knew that would do it when rotating the hub after removing it. The newer one turned smoothly & quietly, but the one just removed did not.

Weird, huh? The most tell-tale sign I can pick-up on after the fact, is that the droning would lessen (or stop altogether, in the beginning) when I was turning or curving RIGHT.

BNaylor
08-17-2006, 08:46 AM
Important thing is you got the issue resolved and can put away that bottle of aspirin. The tap and die kit sounds like a good course of action, otherwise just get another caliper mounting bracket. Probably in abundance at some boneyard since other GM "W" body cars use the same one.

Good luck!

BTW - Forgot to mention check the caliper pin bolt rubber insulator/bushing and make sure it is not causing the bolt to fully insert or thread in.

rickisrad
08-17-2006, 10:35 AM
That hub bearing sound was annoying- I had the same problem. I thought it was the new tires I put on the car. I just replaced it a few days ago along with the struts and it is sooooo much quieter now. The hubs I removed (both sides) just fell apart while I was taking them out so I think they were a little worn. I used the scope to find where the noise is comming from.

rickisrad
08-17-2006, 10:35 AM
That hub bearing sound was annoying- I had the same problem. I thought it was the new tires I put on the car. I just replaced it a few days ago along with the struts and it is sooooo much quieter now. The hubs I removed (both sides) just fell apart while I was taking them out so I think they were a little worn. I used the scope to find where the noise is comming from.

jwardl
08-19-2006, 06:36 PM
Important thing is you got the issue resolved and can put away that bottle of aspirin. The tap and die kit sounds like a good course of action, otherwise just get another caliper mounting bracket. Probably in abundance at some boneyard since other GM "W" body cars use the same one.

Good luck!

BTW - Forgot to mention check the caliper pin bolt rubber insulator/bushing and make sure it is not causing the bolt to fully insert or thread in.
Wasn't the caliper mounting bracket, but the caliper itself.
Can't seem to find the right size tap though... anyone know?

BTW: That bushing can be a bitch sometimes... but that's not the problem. I can't thread the bolt more than a few turns even if I hang-up the caliper from a wire, completely off the mounting bracket.

corning_d3
08-19-2006, 10:14 PM
My drivers side stripped out like that and I went a got a junkyard caliper and rebuilt it...

richtazz
08-21-2006, 08:24 AM
The caliper isn't threaded, the slide pin that goes into the bracket is. The short bolt that retains the caliper to the bracket actually goes into the end of the slide pin. Is it one of these short bolts (or the hole it goes into) that are stripped? If so, buy a new caliper slide pin and matching caliper bolt and you're set. Did you make sure the long sliders that go into the caliper mount bracket are free and sliding properly when you had it apart? If they are seized, it will cause uneven rapid wear of your brake pads.

corning_d3
08-21-2006, 11:34 AM
I just noticed his calipers and slide pins are different than my dual pistons...My slide pin IS the bolt that holds the caliper on..

richtazz
08-21-2006, 12:27 PM
You have a pre-97 Grand Prix/W-body, right Corning?

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