oscillating hum or 'whaaa' sound - LS1GTO.com Forums

Vendors


Go Back   LS1GTO.com Forums > GTO Tech > Drivetrain

Reply
 
Thread Tools Rate Thread
Old 10-15-2012, 05:42 AM   #1
briandors
Registered User
 
2006 GTO Owner

Join Date: Mar 2004
Location: Cleveland, OH
Posts: 301


Offline
oscillating hum or 'whaaa' sound

Hey all.

Just picked up a new GTO Saturday. 2006 M6 SRM with 18000 in Chicago area.

So the first thing I noticed on the test drive was that from 30 to 45mph there is a slow cyclical or oscillating hum, sort of a resonance, it sounds like whaa whaa whaa whaa and the cycles are perhaps every 1-2 seconds. Its not an even pitched hum or whine, like when my first GTO went through two differentials.

At the price I negotiated, I couldn't pass it up, it was well cared for overall. So I drove it home to Cleveland.

I'm thinking of crawling under it tonight and checking the tires and perhaps driveshaft?? Other ideas? It still has the original 18" Bridgestones on it (unless the owner was very aggressive and this is the second set). But I had it up to 100mph on the way home, there is no vibration at any speed, if it was the tires I'd be surprised to only get noise with no shake.

I'm confident its not the brakes.

Maybe there's poly bushings in the drivetrain causing the resonance?

If I can't determine anything it will probably go to Backstreet Performance in Medina.

Thanks for any ideas.

Brian
__________________
Brian D.
2006 SRM M6
  Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 10-15-2012, 05:55 AM   #2
jasen
Insert Witty Title Here
 
jasen's Avatar
 
Monaro CV8

Join Date: Mar 2010
Location: The 'Ville Oklahoma
Posts: 1,879


Offline
Man, I'm anxious to find out what the culprit is too. You've kinda touched on everything I can think of that "might" be causing it.
__________________
06 IBM M6 Monaro CV8Z
Slightly modified - 452+rwhp/409+rwtq

2010 Honda Civic GX - CNG DD. Got tints yo!

2011 Range Rover Sport Supercharged 5.0

Call Late. Call Often:
John Paul Bishop
11222 Kinsale Ct
Ellicott City, MD 21042-6132

(410) 997-0186
  Reply With Quote Quick reply to this message
Old 10-15-2012, 06:20 AM   #3
NormGTO
2004 GTO
 
NormGTO's Avatar
 


Join Date: Apr 2005
Location: OHIO
Posts: 304


Offline
Most like the tires. What are the tire pressures? Might adjust them.
__________________
  Reply With Quote Quick reply to this message
Old 10-15-2012, 06:24 AM   #4
2step
Registered User
 
2step's Avatar
 

Join Date: Sep 2012
Location: Texas Hill Country
Posts: 530


Offline
I've got a bit of that pulsing noise also in my new-to-me '06. Some tires are noisier than others and some cars are also, I guess. My car came with Goodyear Eagle F1 All Season and I have no idea if they might be part of the problem. (I don't know why the last owner went with A/S. This is Texas. We only have one season.) Seems like the sound comes slightly more from the rear.

I do know that my Grand Cherokee is light years more quiet than the GTO w/stock exhaust. Does anyone suspect wheel bearings or maybe noticed things quieting down after new bearings? I might try a few strips of Dynamat around the inside wheel wells and trunk area. When it comes to new tire time, I'm definitely going to shop the noise factor for replacement tires.
  Reply With Quote Quick reply to this message
Old 10-15-2012, 10:28 AM   #5
canttouchthis
Registered User
 
canttouchthis's Avatar
 
2005 GTO Owner

Join Date: Jun 2006
Posts: 1,063


Offline
Is it all stock? Check the drive shaft rubber couplers for cracks. Check the carrier bearing on the two piece shaft. Check the motor mounts. Stock ones go bad and no longer dampen the engine noise from the body.
  Reply With Quote Quick reply to this message
Old 10-16-2012, 04:04 AM   #6
briandors
Registered User
 
2006 GTO Owner

Join Date: Mar 2004
Location: Cleveland, OH
Posts: 301


Offline
Seems to be all stock underneath. Do the stock driveshafts say "MZ" on them?

The tires were around 31psi, I brought them to 35psi and didn't note any change.

I hear a little bit of differential whine -- my ears are well tuned to that sound from experience with the previous GTO. But it's a constant whine not an oscillating sound.

I can only imagine that a slowly oscillating noise means there are TWO noises clashing together, question is, which two. Maybe I'll rotate the tires tonight, the rears are notably more worn than the fronts.
  Reply With Quote Quick reply to this message
Old 10-16-2012, 05:14 AM   #7
n0b0dy1987
Registered User
 
n0b0dy1987's Avatar
 
2005 GTO Owner

Join Date: Dec 2010
Location: Bossier City, LA
Posts: 1,042


Offline
For what its worth, I've had that noise ever since I bought mine at 85xxx miles. I now have 125xxx miles and its still there but never caused me any problems. I've just accepted it. If it ever gets on my nerves I just jam the gas pedal to the floor and let the exhaust note cancel it out.
__________________
2005 IBM,
Performabuilt lvl2 trans
FTI 3600 stall
They who shall not be named LTs
Vararam CAI insulated w/ relocated IAT sensor
TruTrac Installed by Gforce1320
DSS 1pc D/S
Gforce1320 Rear CoilOver setup
12.6 @ 108.3 with a 1.93 60ft and a DA of 3500ft.
  Reply With Quote Quick reply to this message
Old 10-16-2012, 05:24 AM   #8
Poolshark1321
GOATFEST 9 COMING SOON!!!
 
Poolshark1321's Avatar
 
2006 GTO Owner

Join Date: May 2009
Location: League City, Tx
Posts: 2,569


Offline
Do you have contact with the original owner or previous owner? If you do... would get all the information about modifications to the car from them.

Stock drive shaft should be a two piece black... with rubber donuts on both ends and a carrier bearing in the middle. It does have a white tag on it labeled MZ. Like the one in the picture below I provided out of a for sale thread here.



Its worth checking to make sure your carrier bearing bolts are tight and all the driveshaft bolts/nuts are tight as well. It very well could be tire noise, I know when tires get to the end of their life they normally get louder.
__________________
Quote:
Originally Posted by Sticks n Stones...View Post
Mustang's and bricks have alot in common: difference being the mustang comes in more colors.

"Think for yourself and question authority."

Last edited by Poolshark1321; 10-16-2012 at 05:27 AM.
  Reply With Quote Quick reply to this message
Old 10-16-2012, 05:45 AM   #9
briandors
Registered User
 
2006 GTO Owner

Join Date: Mar 2004
Location: Cleveland, OH
Posts: 301


Offline
Yup, that's my driveshaft there. Same color, two piece, donut, etc. I also see the same "MZ" sticker.

It doesn't SEEM like tires, but when two sounds combine and kind of reverberate against each other, it's hard to tell.

I'll check the bolts around the driveshaft.

I bought it from a Ford dealer, but they handed me the title and it shows the previous owner's name and address, so I may tactfully try to make contact with him.

Thanks.
Brian
  Reply With Quote Quick reply to this message
Old 10-16-2012, 05:46 AM   #10
Poolshark1321
GOATFEST 9 COMING SOON!!!
 
Poolshark1321's Avatar
 
2006 GTO Owner

Join Date: May 2009
Location: League City, Tx
Posts: 2,569


Offline
Yeah I know when my eagle f1s were getting to the end of their life they made a shit load of road noise like you are talking about. Soon as I swapped new tires it went away...
  Reply With Quote Quick reply to this message
Old 10-16-2012, 05:59 AM   #11
briandors
Registered User
 
2006 GTO Owner

Join Date: Mar 2004
Location: Cleveland, OH
Posts: 301


Offline
Not to beat a dead horse, but I wanted to make sure I was clear on the noise I am hearing. It's NOT like a 4x4 pickup that is raised and running on huge mudding tires. Although that's an oscillating wawawawawa kind of sound, it oscillates fast and in direct proportion to the speed of rotation of the tire.

My sound is a much slower cycle, perhaps one "waa" per second at 35mph, and it is not consistent in volume, one "waa" could be loud and then the next softer and then back to loud... or you might get two loud ones and then one soft... it's slightly irregular both in its tempo and its volume. Hence my feeling that I have two sound waves clashing.

I'll rotate the tires and check the driveshaft bolts tonight.

Thanks for everyone's help!!
Brian
  Reply With Quote Quick reply to this message
Old 10-16-2012, 06:25 AM   #12
paulsz28
Bolt Extractor
 
paulsz28's Avatar
 
2004 GTO Owner

Join Date: Mar 2009
Location: Goose Creek, South Carolina
Posts: 1,421


Offline
Mine does it, too. It's not really a vibration, just a wha-wha-wha-wha-wha hum. Aroudn the same speeds too, when the exhaust isn't very loud, and neither is the wind or road noise. To me, it sounds like my right rear tire. I'm riding on not-so-sticky Cooper Zeon rubber, and I'm pretty sure those are bottom-of-the-barrel noisy tires.
__________________
2004 PBM M6|109K Miles|Work Commuter
WCS Flat Splitter|Painted Shifter Knob|PDed Lugnut Caps|Llumar 26% Tint
NGK TR5IX|MSD 8mm|180 T-stat + TB bypass|Svede OTRCAI + Omega
Lovells Front RR Bushings + Strut Mounts|Lovells 0-Drop Springs|KYB Shocks/Struts
05/06 Calipers|DBA Standard S/D Rotors|Hawk PC Pads
Kooks SS Headers + O/R Mid-pipes|Stock Asymmetric Mufflers
HSC Stock Height Motor Mounts
Torco RGO|ATE Super Blue Brake/Clutch
  Reply With Quote Quick reply to this message
Old 10-16-2012, 06:34 AM   #13
dizzysn
Registered User
 
dizzysn's Avatar
 
2004 GTO Owner

Join Date: Oct 2009
Location: Boothwyn/Philly PA
Posts: 1,547


Offline
Send a message via AIM to dizzysn
Aftermarket exhaust? Could possibly be exhaust drone.
__________________
RIP - Sgt. James E. Lyons. Apache Company Senior Sniper, 1st 1FT Squadron, 2nd Stryker Cavalry Regiment. Aug 13th, 1987 - Sept 12th, 2011 - KIA.

2004 YJ M6: LS7 clutch, GMM ripshift, Pacesetter LTs, catless mids, SLP LM1, RPM 3 cam: 113LSA 236/242, UDP: 411/375 SOLD

2002 Electron Blue C5 Z06: LS7 clutch, American Racing LTs, XSP exhaust, Vararam CAI, MGW shifter, RPM 3 cam: 114 LSA, 236/242, RPM lvl4 trans: 430rwhp/385ftlbs.
  Reply With Quote Quick reply to this message
Old 10-16-2012, 06:38 AM   #14
briandors
Registered User
 
2006 GTO Owner

Join Date: Mar 2004
Location: Cleveland, OH
Posts: 301


Offline
Stock exhaust.
  Reply With Quote Quick reply to this message
Old 10-16-2012, 06:40 AM   #15
Poolshark1321
GOATFEST 9 COMING SOON!!!
 
Poolshark1321's Avatar
 
2006 GTO Owner

Join Date: May 2009
Location: League City, Tx
Posts: 2,569


Offline
Stock shifter? GMM Race or something similar letting the vibration noises from the drivetrain come inside the cabin more?
  Reply With Quote Quick reply to this message
Old 10-16-2012, 06:46 AM   #16
dizzysn
Registered User
 
dizzysn's Avatar
 
2004 GTO Owner

Join Date: Oct 2009
Location: Boothwyn/Philly PA
Posts: 1,547


Offline
Send a message via AIM to dizzysn
Quote:
Originally Posted by briandors...View Post
Stock exhaust.

Hmm. Wheel hub maybe? Try going about the speed when it starts, and then aggressively going left and right. See if it gets quieter going one way, and louder the other as you load and offload weight from turning. Best to try in an empty parking lot

May also need to get the drive shaft rebalanced. I'd doubt that though.

Last edited by dizzysn; 10-16-2012 at 06:50 AM.
  Reply With Quote Quick reply to this message
Old 10-16-2012, 06:54 AM   #17
briandors
Registered User
 
2006 GTO Owner

Join Date: Mar 2004
Location: Cleveland, OH
Posts: 301


Offline
The only non stock part I have found on the car is a K&N Filtercharger airbox, which I'll be posting up for sale soon as I don't like hearing the throttle body whistle and fortunately the previous owner put the stock box in the trunk.

I have tried the left-right-left-right and don't hear any change, so I don't think its a wheel bearing.
  Reply With Quote Quick reply to this message
Old 10-16-2012, 08:01 AM   #18
dizzysn
Registered User
 
dizzysn's Avatar
 
2004 GTO Owner

Join Date: Oct 2009
Location: Boothwyn/Philly PA
Posts: 1,547


Offline
Send a message via AIM to dizzysn
Quote:
Originally Posted by briandors...View Post
The only non stock part I have found on the car is a K&N Filtercharger airbox, which I'll be posting up for sale soon as I don't like hearing the throttle body whistle and fortunately the previous owner put the stock box in the trunk.

I have tried the left-right-left-right and don't hear any change, so I don't think its a wheel bearing.

Might be the tires then. See if there are any local GTOs that are willing to swap with you for 5 minutes so you can find out.
  Reply With Quote Quick reply to this message
Old 10-16-2012, 08:48 AM   #19
oodn-oodn
Registered lurker
 
oodn-oodn's Avatar
 


Join Date: Aug 2007
Location: Albany, GA
Posts: 518


Offline
I picked up a subtle harmonic hum like you're describing back when I put my Pedders bushings in @ 8k miles, though mine only does it at 75-80mph. I never found the cause & it's not really very noticeable, so I figure it's an inherent NVH thing that the stiffer bushings allow through.

Probably not much help for your situation.
__________________
  Reply With Quote Quick reply to this message
Old 10-16-2012, 09:11 AM   #20
canttouchthis
Registered User
 
canttouchthis's Avatar
 
2005 GTO Owner

Join Date: Jun 2006
Posts: 1,063


Offline
You could "at your own risk" put the rear up on jack stands. support it so the suspension is compressed like its on the road and run it. If the noise is gone its probably your tires. But again its dangerous to do that.
  Reply With Quote Quick reply to this message
Old 10-16-2012, 09:13 AM   #21
paulsz28
Bolt Extractor
 
paulsz28's Avatar
 
2004 GTO Owner

Join Date: Mar 2009
Location: Goose Creek, South Carolina
Posts: 1,421


Offline
Ima drank a barr an gunnit! Ay boy, watchdis! Put yerr head up unna thar and see ifya harr uneethang.
  Reply With Quote Quick reply to this message
Old 10-16-2012, 09:29 AM   #22
Poolshark1321
GOATFEST 9 COMING SOON!!!
 
Poolshark1321's Avatar
 
2006 GTO Owner

Join Date: May 2009
Location: League City, Tx
Posts: 2,569


Offline
^

Yeah tracking down odd sounds can be tricky to say the least. There is a huge section devoted to diagnosing Noises/Sounds in the official Helms repair manuals for the GTOs. Its thick too... but it can be very useful if you happen to have a set of them.

If you do not have a set of them... I would highly recommend any owner that works on their car regularly should purchase a set. You wont have to or always need to use them, but they are very nice to have for when you do need them. The forum is great... combined with the helms manuals, even better.
  Reply With Quote Quick reply to this message
Old 10-16-2012, 09:49 AM   #23
high school goat
Retarded Spark
 
high school goat's Avatar
 
2004 GTO Owner

Join Date: Jan 2008
Location: Charlotte N.C.
Posts: 2,785


Offline
Send a message via AIM to high school goat
Quote:
Originally Posted by paulsz28...View Post
Ima drank a barr an gunnit! Ay boy, watchdis! Put yerr head up unna thar and see ifya harr uneethang.

SIG worthy
__________________
  Reply With Quote Quick reply to this message
Old 10-16-2012, 12:56 PM   #24
Firehawk409
Registered User
 
Firehawk409's Avatar
 
2005 GTO Owner

Join Date: Nov 2011
Location: Gretna, La
Posts: 463


Offline
Send a message via AIM to Firehawk409
mine makes that sound and its coming from my shifter. At first it didnt bother me but now its getting on my nerves. I gotta get this b&m shifter out and put something in that wont be as bad.
__________________
  Reply With Quote Quick reply to this message
Old 10-22-2012, 10:40 AM   #25
briandors
Registered User
 
2006 GTO Owner

Join Date: Mar 2004
Location: Cleveland, OH
Posts: 301


Offline
It's at BSP in Medina, OH now.... Pedders dealer and the locals say they are very good. Hopefully I get good news in the coming days.
  Reply With Quote Quick reply to this message
Old 11-08-2012, 04:54 PM   #26
dizzysn
Registered User
 
dizzysn's Avatar
 
2004 GTO Owner

Join Date: Oct 2009
Location: Boothwyn/Philly PA
Posts: 1,547


Offline
Send a message via AIM to dizzysn
Any update on this or are you still waiting?
  Reply With Quote Quick reply to this message
Old 11-08-2012, 05:12 PM   #27
esau999
O_o
 
esau999's Avatar
 
2006 GTO Owner

Join Date: Oct 2010
Location: DPTX
Posts: 1,347
Premium Member


Offline
Can you record the sound? Makes it a lot easier to diagnose. I get a similar sound with my Gforce 9" rear right at 35 MPH, more apparent when I decelerate in this range of speed - it's not a harmonic or a whine but does sound like a kind of medium-to-low pitched waaa-waaa-waaa. Doesn't sound like grinding, either - almost sounds more like...cavitation...of the gear oil, maybe? I'll be recording mine soon and posting it. I do have poly bushings everywhere, so maybe I have more noticeable NVH.
__________________
4xx/4xx your guess is as good as mine
  Reply With Quote Quick reply to this message
Old 11-09-2012, 05:09 AM   #28
briandors
Registered User
 
2006 GTO Owner

Join Date: Mar 2004
Location: Cleveland, OH
Posts: 301


Offline
They called a couple days after I dropped it off to say they had narrowed it to the differential. Probably some bearings inside it.

They pulled the diff and sent it to a local rebuilder along with a "rebuild kit".

Either while they still had it apart, or maybe after they put it back in, they still heard the noise and have decided it's the needle bearings. They've called Pedders and GeForce and apparently nobody has a set of needle bearings in stock in the USA. So now we're waiting on a boat that is supposed to arrive about a week from now. At this point hopefully I have the car back and fixed in two weeks.

Not sure how much needle bearings cost, I assume BSP didn't order them right off the bat because they were trying to save me some money.

Rich has been very nice to deal with.
  Reply With Quote Quick reply to this message
Old 11-19-2012, 10:19 AM   #29
briandors
Registered User
 
2006 GTO Owner

Join Date: Mar 2004
Location: Cleveland, OH
Posts: 301


Offline
Car still isn't ready.... I spoke with them last week, no needle bearings anywhere in the USA... I let them know I am willing to pay for expedited shipping.... hopefully soon, very few days left before the snow flies.
  Reply With Quote Quick reply to this message
Old 11-19-2012, 02:16 PM   #30
slimbobaggins
Let's roll
 
slimbobaggins's Avatar
 
2005 GTO Owner

Join Date: Oct 2009
Location: Va Beach
Posts: 2,970
Premium Member


Offline
Quote:
Originally Posted by briandors...View Post
Car still isn't ready.... I spoke with them last week, no needle bearings anywhere in the USA... I let them know I am willing to pay for expedited shipping.... hopefully soon, very few days left before the snow flies.

Call Andy @ CSP to see if he has any
__________________
757 GTO Owners Association of Tidewater

http://www.757goat.org/phpBB3/index.php


Quote:
Originally Posted by CoolAid...View Post
Shaking/vibrating/rattling more is actually a bonus to me. I enjoy the Parkinsons effect at a stop light while the car belches out fumes of unburnt fuel from its monster lopey overlap. To me, thats muscle car.

Mods: ARP hardware
  Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the LS1GTO.com Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -8. The time now is 08:42 PM.




Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright 2003-2008, LS1GTO.com
Site Banner Design 2005-2007, Cylosoft

LS1GTO.com is not affiliated with General Motors Corp.