Strange Sound From Manual Transmission Clutch

My truck is a 2005 2500HD with the Duramax Diesel & the 6sp manual transmission. The truck now has about 10,500 miles, so is still under warranty.
For the first 9,000 miles, I did not hear the sound that I am concerned about. After that, with trans in neutral, and as the clutch is released (almost all the way), I begin to hear what I thought was a rattling noise. It came on suddenly (not too loud) & gradually increased in volume over time.
With the trans in neutral & the clutch fully released, the sound is gone. If I depress the clutch just a small amount, the sound returns. The sound can be heard either inside the truck or standing outside by the driver's door. It is not necessary to raise the hood or open the door to hear the sound.
I am someone who pays real attention to noises, smells, etc the truck makes. To me, the sound is unusual & subject for concern.
I took the truck to my local dealer. The service manager agreed something was strange & scheduled an appointment. When I brought the truck in, the diesel mechanic examined it and said the truck was making normal sounds. He said the sound I was hearing was "gears whirring" and nothing to be concerned about.
The sounds are now just a bit louder, but not much. I have driven manual trans vehicles for 35 years & I have never heard such a sound as this before. Admittedly, this is my first truck with the Duramax & 6sp, but I am suspicious.
I'd appreciate your opinions. I am considering taking the truck back to the dealer to ask that it be looked at again. Perhaps a different dealer for a 2nd opinion?
Dave
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Well, Dave, you do need a second opinion. If you're the type of guy that is *overly* concerned about the noise, then you need some satisfaction. First, if you are hearing "gears whirring" you would hear them all the time that the engine is running. The noise you described can be caused by a number of things that all relate to the clutch. The first thing most people would claim as the noisemaker is the throw out bearing. Its pretty common for them to make noise when they start to dry out. Its not real common for them to go so soon. You should probably hear the noise in any gear as the clutch starts to engage, but in forward and reverse, there is a transfer of power involved that may lessen the sound. Consider your dealer. The service manager heard it and said it sounded strange. If you take it back, you might get the same runaround. I'd suggest a second dealer if its not a problem. A new set of ears might confirm your suspicions.

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As my clutch is released, the engagement point is reached about 1/2 way up. The noise is heard (I'd guess) about 90% of the way up, that is past the clutch engagement point. The clutch seems to be engaged at the "noise" point. I probably hear the noise in all gears, even when I leave a stop sign. However, a diesel is not the quietest of engines & probably masks the noise when actually driving. The noise is not heard at any point in the clutch travel except at this "90% noise point". The symptoms occur exactly the same whether or not things are warmed up (driven a bit).
An interesting point is that when I first brought the truck to the dealer, the service manager agreed there was a noise & it probably was the throw-out bearing. However, when I brought the truck back for the repair appointment, the mechanic said no problem.
I plan on taking the truck to another dealer as soon as I can. Since the other dealer sells the same make/model truck, warranty repair at a different dealer should not be a problem.
wrote:

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Not enought Fluid in the Transmission..
Dave wrote:

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Dave wrote:

Excessive Shifter and/or Engine Vibration, Bearing Growl and/or Rattle Type Noise While Depressing or Releasing Clutch Pedal (Replace Flywheel and Flywheel Mounting Bolts) #04-07-31-006A - (Dec 9, 2004) Excessive Shifter and/or Engine Vibration, Bearing Growl and/or Rattle Type Noise While Depressing or Releasing Clutch Pedal (Replace Flywheel and Flywheel Mounting Bolts) 2001-2005 Chevrolet Silverado
2001-2005 GMC Sierra
with 6.6L DuramaxT Diesel (RPOs LB7, LLY) and Manual Transmission (RPO ML6)
This bulletin is being revised to add the 2005 model year, VIN breakpoints and include the replacement of the eight flywheel mounting bolts. Please discard Corporate Bulletin Number 04-07-31-006 (Section 07 -- Transmission/Transaxle).
Built Prior to the following VIN Breakpoints:
Plant VIN Breakpoint
Flint, MI 5F836256
Pontiac, MI 5E148789
Condition Some customers may comment on a bearing growl or rattle-type noise while depressing or releasing the clutch pedal. Some customers may comment on excessive shifter or engine vibration. In some cases, the excessive vibration may result in an injector balance rate fluctuation condition.
Cause The steel clutch thrust washer may wear down the flywheel bushing prematurely, causing an excessive vibration condition.
Diagnostic Tips The bearing growl/rattle-type noise and or vibration is eliminated with the clutch fully engaged or disengaged.
Correction Replace the flywheel assembly with a Dual-Mass Flywheel, P/N 24232434. Refer to the applicable SI procedure below.
Important: The eight flywheel mounting bolts, P/N 97226124, must be replaced when service requires removal or replacement of the flywheel.
Ian
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IAW a sticker on the driver's door, my truck was built in Flint, MI. I took delivery on the truck from my local GMC dealer Sept 14, 2004. The VIN# is: 1GTHK23255F825655. From your posting, it appears that my truck is effected.
Personally, I have never seen a GMC bulletin. Your posting says to discard bulletin 04-07-31-006. Is there a new bulletin number? Is there any way I can get a copy of the applicable bulletin? My local dealer does not believe there is a problem. I would like some evidence to convince him.
Dave
On Sat, 12 Feb 2005 17:47:41 GMT, "shiden_kai"

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Dave wrote:

I just gave you the applicable bulletin! The reason that it says to discard bulletin 04-07-31-006 is because "it" (the bulletin I copied for you) is version 006a. Don't get worried about all that stuff, that's simply internal stuff for the dealer. The bulletin I quoted is the latest. Take that number in to the dealership (the one with the "a") and see if they think it applies to your situation.
Ian
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Ian:
Thanks for the info. I appreciate the time you took to help me.
I would like to find a good source of TSB's for my truck. I tried alldata.com, but the TSB you referred to was not available. I used the TSB# you provided as a sample to search alldata's database.
I am willing to pay any reasonable price for the TSB's. Helm will sell them, but you need the TSB number first.
Do you know of any source besides alldata.com that has a complete selection of TSB's for my truck, or at least a database of TSB numbers & descriptions?
Dave
On Sun, 13 Feb 2005 21:21:23 GMT, "shiden_kai"

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Dave wrote:

Well, yes....I have access to GM's online Service Information...but it's not available to the public. Are you not able to simply print out the newsgroup message that I sent with the TSB in the body? That's what I was attempting to do, give you the full copy of the TSB in the newsgroup message, all you have to do is make a copy of it.
Unfortunately, I can't sell you the TSB's, but I can and will copy them for you in a newsgroup message. If you want to simply browse through all the bulletins that pertain to your truck, I can't help you there. For the most part, that would end up being interesting, but a big waste of your time. You would see issues that will probably not appear on your truck, but will end up worrying you to no end. Or, you might end up being the kind of person that we see occasionally in the dealership...always in there with handfuls of bulletins demanding this/that/and the other be fixed. Bulletins are designed to apply to a problem that your vehicle "might" have. Even I (some techs might) don't bother trying to read "all" the bulletins...it's too tedious. If it's a slow day, I might browse the "new" bulletins to see what's coming down the line, and every now and then I catch an interesting bulletin that I'll be able to use, but for the most part, I don't bother with looking up bulletins until I'm faced with a particular problem.
Ian
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Ian:
To date, I have visited the dealer 3 times. The check engine light came on (required a software update), routine maintenance, and this noise problem. I will return to the dealer with the TSB you sent. I was able to copy it easily from the newsgroup. Thanks for the help!
The reason for asking for a source of TSB's is merely personal curiosity. I've always serviced my own vehicles in the past. But, with the increasing complexity of modern cars & trucks, this is getting much more difficult.
I've read summaries of TSB's in alldata.com & mycarstats.com. All I have seen are vague summaries. I've also found these sources rather incomplete. After browsing these summaries, it became rather obvious that browsing TSB's is a waste of time unless you have a specific issue to solve.
Would you object to sending me an email address? The email address for me ( snipped-for-privacy@nordquist.us) is valid.
Dave
On Wed, 16 Feb 2005 05:36:03 GMT, "shiden_kai"

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Hi,     It sounds most likely like a clutch throw out bearing. If your tranny is making noise I would first suspect lubrication. Check your tranny fluid level. If it is the tranny most likely it is a bearing. Shift forks or linkage are not likely bad as they don't spin. A sharp gear from lack of lube or bad design will also make a whirring noise. Your clutch obviously disengages the tranny. if you have the truck in nuetral you are not engaging the output shaft. Your clutch does not put any pressure on the tranny what so ever. If it's all in clutch movement it is your throw out bearing. Another thing that could be bad is a bad tranny mount. Sometimes these flatten and the tranny rests on the cross member and transferes noise to the body. Good luck. Jessie
Dave wrote:

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