Clunk Revisited

Jersey Tahoe LT · July 23, 2003

Sorry for bringing up the never ending topic. BUT. This past weekend I took my truck offroad and Everthing was fine afterwards. I got home and washed her off. And that night I went out and took my truck and there were no problems. Well The next day I was driving and I hit my breakes and it was wobbly like the rotors were warped again. Then that went away after 5 min. No biggie. Well then the next day (Monday) since it has the drive line Clunk feel but it is a lttle different feeling. As if something is lose under there. And at Idol in gear (D,1,2,3 nad R) the truck vibrates as if the Idol is higher and wanting to move. It is enough to make the Drivers side rearveiw Mirror vibrate. I am not to conserned since I feel no power loss of any kind. But Really want your thoughts. Could I hav losened the rearend? Could I have gotten contaminated water in the rear end? Could I have killed my rear Drive Shaft U-Joints? It also seems to have a barking sound when I hear the clunk. Could I have wiped out the Greese from the Yoke. I never want through water over the middle of the wheel. But I did splash a lot around. And while cruising and just about up to speed it seems to have a little whine to it. Like Tire noise but not from the tires? I am at a loss and I will be looking into it this weekend. Thanks for any help in advance. You have all always been a great Help.

Later,

Brandon

Shaners · July 24, 2003

Give her a grease job and check the rear-end fluid level (Maybe a little water went in the vent). Grab the driveshaft and give it a couple of yanks and twists and see if there is any slop in the universals...

Check the motor mounts and leaf springs and make sure they are all in good shape and that there isn't any debris stuck in there...

artt · July 24, 2003

Whenever I read about driveline clunk I repost this TSB. The problem is the crush sleave behind the pinion, it moved too much, the ring and pinion need shimming.

Info - Driveline Clunk #99-04-20-002A

Driveline Clunk

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.

Jersey Tahoe LT · July 24, 2003

Thanks Shanners I will look through all of those. And ARTT, thanks for the TSB but it is more the at the line clunk. But I will look into all of these. Thanks a bunch. Any more Comments welcome.

Later,

Brandon