I have done a search, which revealed that a clutched alternator / special (kevlar) belt may be the solution to my problem. We own a 2006 LBZ SB/EC 2500HD. From day one there was a shutoff chirp which I always considered normal. Many people described this as a "turbo brake" which I knew was total bullcrap since I am a GM technician. Others said the heavy rotating internal parts of the diesel come to a stop fast and the belt slips, which made more sense. I understand the clutched alternator that comes on later trucks eliminates this problem, but it has never bothered me. However, lately (with 20k miles now), there is a pronounced belt chip for the first five minutes of warm-up, especially in cold/wet conditions. Furthermore, the condition seems to have worsened as there is now an annoying belt chirp / sqeek for the first 10 minutes of every cold start up even in moderately cold / wet conditions. For the sake of the comfort / luxury of my $40k 2006 truck I want to correct this symptom. My service manager at work (I am a GM technician) responded to my mention of a clutched alternator by telling me to try "pushing in the power steering pulley". Apparently this procedure has corrected belt squeek conditions on other trucks. However I would like to know the true cause / solution for the cold belt chirp noise on the LBZ before I go messing with stuff. Thanks in advance to your suggestions.

Roland

i own a lb7 and my belt started a steady squeek. i ended up just replacing the belt ( origional with 60k miles on it) and it cured the problem. i know this trick works on most rigs, take a bar of soap and while the engine is running let the belt rub on it. usually cures the squeek.

Belt chirp on shut down is the alternator. There is/was a TSB on replacing with an updated clutched alternator. Belt squeek on start up or while running is typically solved with adjustment to the bracket/power steering pulley. From the factory there was an alignment problem. They may need to replace the bracket or enlargen the holes to get the proper adjustment. There is a TSB on this as well IIRC.

I have done a search, which revealed that a clutched alternator / special (kevlar) belt may be the solution to my problem. We own a 2006 LBZ SB/EC 2500HD. From day one there was a shutoff chirp which I always considered normal. Many people described this as a "turbo brake" which I knew was total bullcrap since I am a GM technician. Others said the heavy rotating internal parts of the diesel come to a stop fast and the belt slips, which made more sense. I understand the clutched alternator that comes on later trucks eliminates this problem, but it has never bothered me. However, lately (with 20k miles now), there is a pronounced belt chip for the first five minutes of warm-up, especially in cold/wet conditions. Furthermore, the condition seems to have worsened as there is now an annoying belt chirp / sqeek for the first 10 minutes of every cold start up even in moderately cold / wet conditions. For the sake of the comfort / luxury of my $40k 2006 truck I want to correct this symptom. My service manager at work (I am a GM technician) responded to my mention of a clutched alternator by telling me to try "pushing in the power steering pulley". Apparently this procedure has corrected belt squeek conditions on other trucks. However I would like to know the true cause / solution for the cold belt chirp noise on the LBZ before I go messing with stuff. Thanks in advance to your suggestions.

Roland

In my business park, the guy 2 suite's down has been having
this problem on his new LBZ. The dealer finally fixed it by
realigning the power steering pump.

There are 3 or 4 other threads on this already. None of those helped you out?

well if you are a gm tech, then you have access to SI, here is the document number you need for your cold start belt noise

Document ID# 1870272

Thank you all. Cobra, the Doc. ID was especially helpful. In order to make this thread more useful / informative, I am posting the bulletin. That way others may run into it while they are searching and won't have to start a thread like dumb little me.

Document ID# 1870272


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Subject: Cold Start Belt Chirp - keywords AC A/C accessory air bracket compressor conditioning diesel drive engine idle LBZ LLY mounting noise power pump rattle squeal squeak steering #PIP3965 - (11/02/2006)



Models: 2006-2007 Chevrolet Express, Silverado

2006-2007 GMC Savana, Sierra

Equipped with the 6.6L diesel engine RPO codes LBZ and LLY




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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
The customer concern may be a accessory drive belt chirp, squeal, or squeak noise at idle. The noise may be reduced or gone after the engine warms up.

Note: Please do not replace the accessory drive belt for this concern. If the belt is replaced, the noise may temporarily diminish, but return after the belt breaks in.

Recommendation/Instructions:
2004-2007 C/K trucks & 2006-2007 G Vans, with a 6.6L LLY engine produced before June, 2004 may have an A/C compressor/power steering pump mounting bracket and power steering rear mounting bracket that are machined slightly out of specification.

Vehicles built with a 6.6L LLY or LBZ engine after June 2004 will already have the new A/C compressor/power steering pump mounting bracket installed, but still may exhibit belt noise caused by the power steering pump rear mounting bracket and/or Power Steering Pulley alignment.

Please refer to bulletin number 05-06-01-018 for 2004 to 2005 vehicles and belt chirp.

For the 2006 and 2007 LBZ and LLY engines complete the procedure below.

Remove the rear power steering bracket bolts that bolt to the A/C compressor/power steering pump bracket.



Loosen the front power steering pump bracket bolts that bolt to the A/C compressor/power steering pump bracket.



When reinstalling the bracket, torque the front mounting bolts to 50Nm (37 lb ft). Do not reinstall the rear power steering mounting bolts that bolt to the aluminum bracket. (The front power steering pump bracket bolts must always be tightened first to ensure correct pulley/bracket alignment)
Use a mirror and flashlight to observe the alignment between the rear power steering bracket bolt holes and bolt holes in the aluminum bracket. If the holes are aligned properly install the bolts and torque to 50Nm (37 lb ft).
If the holes do not align properly replace the rear power steering bracket with part number 97209551.
Install the rear bracket and torque bolts to 50Nm (37 lb ft).
Note: If the noise was not fully eliminated the Power Steering Pulley may be adjusted a maximum of 1 mm (.039") to the front from the flush position on the shaft to assist in eliminating any remaining belt noise.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.



GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
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© Copyright General Motors Corporation. All Rights Reserved.


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Document ID# 1870272

Does this "chirp" go away after it is started? Is it really that annoying? Does it do it every single time? Just asking...

http://dieselplace.com/forum/showthread.php?t=114174&highlight=squeak

It goes away after the truck is fully warmed up. It's not something I couldn't live with, but it's not cool when your brand new truck sqeeks and chirps continuosly for the first 15 minutes at idle, especially on cold and/or wet mornings.

It goes away after the truck is fully warmed up. It's not something I couldn't live with, but it's not cool when your brand new truck sqeeks and chirps continuosly for the first 15 minutes at idle, especially on cold and/or wet mornings.

My squeek on startup was a bad idler pulley. Squeek was remedied but chirp remains on shutdown. I cannot do the alternator because my truck has dual's.

Turn the radio up then you will not hear the chirp.

i fixed mine last night, i got the bracket in the tsb but did not use it. i just pushed the p/s pulley in about 1/32 and it has not done it since. i brought it in last night squeaking like crazy adjusted the pulley and it cleared right up!!!!!

My squeek on startup was a bad idler pulley. Squeek was remedied but chirp remains on shutdown. I cannot do the alternator because my truck has dual's.

Okay, I was wrong.The squeek was back today...? Not sure if I should go ahead and push that pulley in or not at this point? Any suggestions?
For those of you who have, did the belt look aligned or not? Mine looks aligned well.

i could see on the back of my belt were it was rubbing so it just made since to push the pulley. no more chirp!!!!

Hey everyone, I'm new to the group. I have a 2006 LBZ with about 15K on it, and I'm also having trouble with my belt in similar conditions. I prefer to stay away from temporary solutions such as belt dressing or other lube. I had a 2002 LB7 with the same problem. I put a Goodyear Gatorback belt on it and it never squeaked again...ever. Last time I checked they hadn't come out with one for the LBZ yet, but that was a while ago so they may have a part # now.

Hey everyone, I'm new to the group. I have a 2006 LBZ with about 15K on it, and I'm also having trouble with my belt in similar conditions. I prefer to stay away from temporary solutions such as belt dressing or other lube. I had a 2002 LB7 with the same problem. I put a Goodyear Gatorback belt on it and it never squeaked again...ever. Last time I checked they hadn't come out with one for the LBZ yet, but that was a while ago so they may have a part # now.

Yes, they do, check with summitracing.com. They are backordered but they said mine should be here in about 2 weeks. Do some searches, you should find the part numbers or just ask the sales at summit.

I did the alt TSB and the pulley alignment and everything else !!! I was under the hood doing the headlight all on mod and noticed "strings" down by power steering pump, after further investigating I found it was coming from the belt!! It's coming from the back side. WTF.... The funny thing is I have no noise at all, but we also havn't had any cold weather ay all. The truck only has 5000 miles on it!!

Mine has squealed from day one. Dealer came and got it and two days later they delivered a squeaking truck back to me. They adjusted the power steering pump. Still squeaks constantly. Might just do it myself.

I am not going to deal with the stealer anymore. Mine is squeaking again and I am going to pick up a gatorback belt from advance auto ($36). Hopefully that cures it.

I have had the alternator changed,2 new belts and the tsb they said they did still squeaking also when I first got the truck it leaked inside from the marker light on the roof through the upper console said they fixed leaking again also under the truck greasing found cooling line for tranny leaking brought it in had the truck all day called me to pick it up because the line would take over a month to get told me keep an eye on the tranny fluid wtf everything needs to be ordered they cannot find a damn tranny line in the US overnight it.I would hate to see if something really went wrong it would be a year to get all the parts and 4 years to fix it properly.

Your dealer sucks. Come down to Homestead. We treat Duramax good.

I have had squeak since new and after 22K miles installed Gator belt from advanceauto.com. Now have 24K and counting. so far no more squeak.