Clunking And Or Clanking Noise

[dixond72]

Hello I have a 2004 silverado 1500 4wd Z71 crew cab short box when i come to and accelerate form an stop there is a clunking or clanking noise I had it to the deeler several times for excessive rear end clunking and they say that it is normal. Am i making too much out of nothing? thanks in advance.

[2004crewcab]

Hello I have a 2004 silverado 1500 4wd Z71 crew cab short box when i come to and accelerate form an stop there is a clunking or clanking noise I had it to the deeler several times for excessive rear end clunking and they say that it is normal. Am i making too much out of nothing? thanks in advance.

 

 

i was told it was the slip yoke on my truck.

[GMTRUCKTECH]

Here is some info that may help.

 

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Subject: Information on Driveline Clunk Noise When Shifting Between PARK and DRIVE, PARK and REVERSE or DRIVE and REVERSE #99-04-20-002D - (06/08/2006)

 

 

 

Models: 2007 and Prior GM Passenger Cars and Light Duty Trucks

 

2007 and Prior HUMMER H2, H3

 

2005-2007 Saab 9-7X

 

 

 

 

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This bulletin is being revised to add models and model years. Please discard Corporate Bulletin Number 99-04-20-002C (Section 04 -- Driveline/Axle).

 

 

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Important: The condition described in this bulletin should not be confused with the following previous bulletins:

 

• Info - Discontinue Flushing and Replacing Transfer Case Fluid Due to Bump/Clunk Concern (Corporate Bulletin Number 99-04-21-004A or newer).

 

• Clunk, Bump or Squawk when Vehicle Comes to Complete Stop or Accelerating from Complete Stop or Accelerating from Complete Stop (Replace Rear Drive Shaft Nickel-Plated Slip Yoke) (Corporate Bulletin Number 01-04-17-004B or newer).

 

 

Some owners of vehicles equipped with automatic transmissions may comment that the vehicle exhibits a clunk noise when shifting between Park and Drive, Park and Reverse, or Drive and Reverse. Similarly, owners of vehicles equipped with automatic or manual transmissions may comment that the vehicle exhibits a clunk noise while driving when the accelerator is quickly depressed and then released.

 

Whenever there are two or more gears interacting with one another, there must be a certain amount of clearance between those gears in order for the gears to operate properly. This clearance or freeplay (also known as lash) can translate into a clunk noise whenever the gear is loaded and unloaded quickly, or whenever the direction of rotation is reversed. The more gears you have in a system, the more freeplay the total system will have.

 

The clunk noise that owners sometimes hear may be the result of a buildup of freeplay (lash) between the components in the driveline.

 

For example, the potential for a driveline clunk would be greater in a 4-wheel drive or all-wheel drive vehicle than a 2-wheel drive vehicle. This is because in addition to the freeplay from the rear axle gears, the universal joints, and the transmission (common to both vehicles), the 4-wheel drive transfer case gears (and their associated clearances) add additional freeplay to the driveline.

 

In service, dealers are discouraged from attempting to repair driveline clunk conditions for the following reasons:

 

• Comments of driveline clunk are almost never the result of one individual component with excessive lash, but rather the result of the added affect of freeplay (or lash) present in all of the driveline components.

 

Because all of the components in the driveline have a certain amount of lash by design, changing driveline components may not result in a satisfactory lash reduction.

 

• While some owners may find the clunk noise objectionable, this will not adversely affect durability or performance.

 

• For additional diagnostic information, refer to the appropriate Service Information.

 

 

 

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.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

 

 

© Copyright General Motors Corporation. All Rights Reserved.

 

 

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[7egend]

my AWD SD has the same clunk sound described it's not as loud as some trucks I've heard but I can hear it once in a while. But generally I dont hear it.

 

As far as affecting performance and durability I say it will affect over all life of the drive line cause that "clunking" is the slapping of two metal gears and when they slap shaving come off of those gears. How long it actually takes for something like this to cause a real problem is unknown to me, but I am sure it will take longer than 5 years/100,000 miles, thats why it's not a big deal for GM to say oh it's nothing.

[lucentj]

my AWD SD has the same clunk sound described it's not as loud as some trucks I've heard but I can hear it once in a while. But generally I dont hear it.

 

As far as affecting performance and durability I say it will affect over all life of the drive line cause that "clunking" is the slapping of two metal gears and when they slap shaving come off of those gears. How long it actually takes for something like this to cause a real problem is unknown to me, but I am sure it will take longer than 5 years/100,000 miles, thats why it's not a big deal for GM to say oh it's nothing.

 

 

I experience the same noise and when reported to the dealer I was also told it's normal. Every time I have someone new in my truck they tell me I really need to get that checked out. Of course I am well beyond my warranty of 30,000K so if something does go wrong I am just SOL

[Cranky1]

I just bought a 2004 LT K1500 crew cab (59,000 Kms) 2 weeks ago and it is out of warranty. The day I test drove it, the box was full of ice and snow up to the bed rails. I noticed a slight clunk once 1 took my foot off the brake from a stop to start moving again. After picking the truck up from the dealer with no snow or weight in the back, the clunk is a lot worse. I had a load of wood and dry wall the other day and I could hardly notice any clunk as it was loaded.

 

The harder I come to a stop, the worse the clunk will be taking off. The slower I take my foot off the brake, I will get a series of clunks.

 

In my opinion, it seems as you are braking, the rear diff is rolling on the leaf springs changing the angle of the pinion, the drive shafts slip yoke slides upwards. When letting your foot of the brake the slip yoke ratchets back (clunks) as the leaf springs return to their normal stance.

 

I have to agree, it is a pain in the a$$.

 

Is there a lube we could use on the slip yoke?

 

Opps, I better change my signature.