04 tranny

[snarkee]

last month i purchased a new 2004 silverado 1500 ext 4x4 with the 4.8 auto

 

I noticed that i constantly hear clunking noises when the truck shifts from 1-2 and 2-3....whether its up or downshift....i also noticed this on 2 other 04 trucks but mine is alot worse...its very annoying.

 

any fix?

[sperry]

"Information on 2-3 Upshift or 3-2 Downshift Clunk Noise #01-07-30-042B - (Jan 16, 2004)

 

2004 and Prior Light Duty Trucks

 

2003-2004 HUMMER H2

 

with 4L60E or 4L65E Automatic Transmission (RPOs M30, M32)

 

This bulletin is being revised to add the 2004 model year. Please discard Corporate Bulletin Number 01-07-30-042A (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."

 

They've programmed it to a tolerable level, described in other bulletins.

 

Another one:

 

"Info - Driveline Clunk #99-04-20-002B - (Aug 21, 2003)

Driveline Clunk

 

2004 and Prior Light Duty Truck Models

 

2003-2004 HUMMER H2

 

This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 99-04-20-002A (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 99-04-21-004A.

 

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."

 

The "Important" referred to a bulletin for early 90's vehicles.

[99silveradoz71]

Thanks. My parents' neighbors were asking me to ask about their 04 1500 crew that's been clunking between 1-2 I believe.

[snarkee]

thanks...but its not the info i wanted to hear

 

I guess i am going to have to live with the clunking

[snarkee]

left it at the dealers today.....when i put it in 4x4 it shifts like a caddy...no thumps....in 2wd i get a bad 2-3 thud in the front end...hope theres a fix