Anyone else notice a slight "clunk" feel (no noise) when taking off from a stop, or coming to a stop? I'm guessing it is just the driveshaft perhaps. It has been there since the truck was new, is that common?

Tony

 

sounds like some play in the drive line.............

 

check your u joints, that is typical of worn u joints.

 

This is the exact problem I had when I bought my 2003 Silverado. The dealer fixed it by lubing the slip yoke(spelling)a ton and changing the transfer case fluid to a new type of fluid that I can't remember what it is called but they said it is bule in color. They said the slip yoke was sticking and is somehow tied into the transfer case. They 1st just lubed the slip yoke and that fixed the problem for a couple weeks but came back so then the changed out the transfer case fluid and lubed the slip yoke again. 6,000 miles later it never came back! Good luck!

 

Here is some info

Driveline - Clunk Explanation

File In Section: 04 - Driveline Axle

Bulletin No.: 99-04-20-002A

Date: September, 2001

INFORMATION

Subject:
Driveline Clunk

Models:
2002 and Prior Light Duty Truck Models

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

Important: The condition described in this bulletin should not be confused with Driveline Stop Clunk, described in Corporate Bulletin Number 964101R (Chevrolet 92-265-7A, GMC Truck 91-4A-77, Oldsmobile 47-71-20A, GM of Canada 93-4A-100) or Bump/Clunk Upon Acceleration, described in Corporate Bulletin Number 99-04-21-004.

Some owners of light duty trucks 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.


And another:
A/T - 2-3 Upshift or 3-2 Downshift Clunk Explanation

File In Section: 07 - Transmission/Transaxle

Bulletin No.: 01-07-30-042A

Date: December, 2002

INFORMATION

Subject:
Information on 2-3 Upshift or 3-2 Downshift Clunk Noise

Models:
2003 and Prior Light Duty Trucks
with 4L60E or 4L65E Automatic Transmission (RPOs M30, M32)

This bulletin is being revised to add the 2003 model year as well as information about 3-2 downshift Please discard Corporate Bulletin Number 01-07-30-042 (Section 07 - Transmission/Transaxle).

Some vehicles may exhibit a clunk noise that can be heard on a 2-3 upshift or a 3-2 downshift.

During a 2-3 upshift, the 2-4 band is released and the 3-4 clutch is applied. The timing of this shift can cause a momentary torque reversal of the output shaft that results in a clunk noise. This same torque reversal can also occur on a 3-2 downshift when the 3-4 clutch is released and the 2-4 band applied. This condition may be worse on a 4-wheel drive vehicle due to the additional tolerances in the transfer case.

This is a normal condition. No repairs should be attempted.


This is a problem I'm haveing

Drivetrain - Launch Shudder/Vibration On Acceleration

File In Section: 04 - Driveline Axle

Bulletin No.: 02-04-17-001A

Date: July, 2002

TECHNICAL

Subject:
Launch Shudder/Vibration on Acceleration
(Replace Propeller Shaft and Install New Pinion Flange/Seal)

Models:
1999-2003 Chevrolet Silverado 2WD 1500 Series
Extended Cab Short Box Pickups
1999-2003 GMC Sierra 2WD 1500 Series Extended Cab Short Box Pickups
With 4L60-E Automatic Transmission (RPO M30)
Except QUADRASTEER(TM) (RPO NYS) Equipped Vehicles

This bulletin is being revised to add Model information. Please discard Corporate Bulletin Number 02-04-17-001 (Section 04 - Driveline Axle).

Important: Implementation of this Service Bulletin by "GM of Canada" dealers requires prior District Service Manager approval.

Condition

Some customers may comment on a vibration when accelerating from a stop. This is also known as launch shudder. This condition may occur between 0-40 km/h (0-25 mph) and be more noticeable when the vehicle is carrying cargo or used for towing.

Correction

A new propeller shaft, P/N 15071486, has been developed to correct this condition. The new propeller shaft incorporates dual double cardan joints on the center and rear joint positions. Refer to Corporate Bulletin Number 02-00-90-002 for lubrication information.

The new propeller shaft will require the installation of a new pinion flange kit, P/N 15071485. The pinion flange kit consists of the following components:

^ A pinion flange

^ Hex bolts (four)

^ A pinion seal

^ A rear axle drive pinion nut

 

BTW, yes it seems to be common. They have a redesigned nickle plated slip yoke that is supposed to be a fix for severe problems.

 

I had the same issue on my 99. It wasn't the driveline, U joints, or yoke. It was the rear leaf springs. The plastic pad on the lower helper leaf would make the noise. It happens at start and start during the weight transfer, the helper leaf will com into contact with the leaf above it and "chirp" or "clunk". Dealer fixed it by installing rubber boots over the end of the spring and giving it a thick coat of grease. After a year, it started coming back, but I just relubed the boot, and all was well.

Test it by putting a dab of grease on the plastic pad on the lower leaf.

 

Thanks Greg, those describe the clunk exactly. As long as the above quote is valid, I'm okay with it. Damn clunky GMs

I'll lube up the slip yolk and leafs this weekend.

Tony