2004 Silveradoe Transmission Clunk

[Hookmaster]

I have a 2004 Z71 half-ton crew cab. Almost daily the transmission will clunk a few times when driving normally (not fast) while it is upshifting from 1-2 or 2-3 or downshifting from 3-2 or 2-1. I had it in once and they said this was normal since the 4X4s need more play in the transmission. My previous 2 vehicles were an S10 pickup and S10 Blazer, both 4X4s, and neither did this. Anybody have this issue? I also can see a little wet spot on the rear differential where the drive shaft connects. No gear oil on the driveway or hanging from the differential. The service guy said this was normal. I'm coming up on 30,000 warranty expiration and want to get these fixed if needed. Any thoughts are appreciated. Is there a HSOforum that deals with Silverado issues?

[ricqik]

If it's clunking during the shifts then your tranny is going to go out, when I don't know but it's a sympton. If it's clunking while rolling along, you probably have a broken gear tooth peices floating around in the tranny or rear diff and when that little metal fragment gets caught in between the gears it make a clunk.

This may not be your problem but just something to think about.

[eyepatrol]

Hook....

I've got a 2003 1/2 Ext. Cab Z71 Silverado (5.3L) and it does the EXACT same thing while shifting through the exact same gears. I brought my truck in on two different occassions to two different places and both told me it was normal. There was even a memo from Chevy they showed me where there was a lot of concerns/questions coming in from consumers regarding this very thing. Chevy along with the dealers say it's normal and nothing to worry about. Diagnostics were done on my truck and nothing turned up. However, if there ever is a problem, the dealer told me they have it on record that I voiced concern...for whatever that might be worth (nothing probably).

Anyway, I too have the same thing happening and have been told from two different dealers that it's normal.

[rosspj59]

I have an 2003 silverado and I have had the same situation as basscatcher. I was told it was normal too. I did purchase an extended warranty though just in case.

[spudhauler]

I really don't know, but are you sure it is not the rear diiferntial that is locking. My 04' chevy does the same thing, but I was told it is the locking rear diff.

[harvey lee]

My son had a knock in the bottom end of a new Chevy truck.He took it to the dealer and they said it was normal.I never heard a normal knock in the bottem end.We wrote to GM and had them extend the warranty for the motor and state that we contacted them about this knock.Drove the truck to 80,000 and traded it in.

[Gus]

I'll join the ranks. Have 03 silverado... dealer says normal.

I notice it more the easier I drive it. 85,000 miles now. Tranny fluid never looked or smelled burnt when I replaced it at 50,000. So far problem has not gotten worse or better.

[LMITOUT]

I'm betting it's the infamous driveshaft clunk. Had it on my '99 Z-71 but it typically occurred leaving a stop and approaching a stop. The input yoke on the driveshaft where it enters into the rear of the tranny sticks and then releases causing a clunk when the rear axle rotates during acceleration and deceleration. The yoke is supposed to move forward and backward naturally, but they start to stick a little bit over time.

There used to be a procedure issued by GM where they would drain the transfer case fluid and replace, then drive for a few miles and then drain and replace again. Thought it was weird but it did work.....for a while then it was back again. Eventually they started coming with nickel plated yokes to help the problem.

If it is what I've described it's nothing to be concerned about and more of an annoyance than anything.

[Hookmaster]

Thanks guys. I drive it pretty easy and most of the time it happens when taking of from a stop or coming to a stop. I searched on the internet and found this:

From General Motors to their Dealers:

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

Date: August 21, 2003

Subject:

Drive line Clunk

Models:

2004 and Prior Light Duty Truck Models

2003-2004 HUMMER H2

Important: The condition described in this bulletin should not be confused with Drive line Stop Clunk, described in Corporate Bulletin Number 964101R (Chevrolet 92-265-7A, GMC Truck 91-4A-77, Oldsmobile 47-71-20A, GM of Canada 934A-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 free play (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 free play the total system will have.

The clunk noise that owners sometimes hear may be the result of a buildup of free play (lash) between the components in the Drive line.

For example, the potential for a Drive line 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 free play 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 free play to the Drive line.

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

· Comments of Drive line clunk are almost never the result of one individual component with excessive lash, but rather the result of the added affect of free play (or lash) present in all of the Drive line components.

Because all of the components in the Drive line have a certain amount of lash by design, changing Drive line 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.

[Hookmaster]

Does this happen in the Suburbans and Tahoes also?

[Little Joe]

Yup, my '04 burb does it now. Used to own a '98 1/2 ton ext cab that did the exact same thing. Neither have let me down to date..

[walleyeaddict]

Simple solution...sell the chevy and buy a Ford!!! They drive till they rust apart!!!

[eyepatrol]

I wouldn't go that far with the Ford thing...owned one almost all my driving life and can say differently.

As for the Suburbans and Tahoes, my wife drives our '05 Tahoe and I haven't noticed it on her vehicle yet, although we're usually talking and I'm not paying attention for it either. It's got about 25,000 miles on it and my '03 Silverado has about 38,000 miles.

And yes, my truck "clunks" when approaching a stop or accelerating from one, but doesn't occur if I'm turning onto a highway and gassing it to get up to speed...smooth as silk in those conditions.

[jwhjr]

I just had my 04 in for my laundry list of things to check before the 36K warranty is up, and the 2-3 shift clunk was on my list. I knew about the bulletin stating it was "normal", but I figured it wouldn't hurt to log my concern. What they did end up doing was a PCM reprogram, but I haven't driven it enough to determine whether or not it has made a difference yet. I'll put a few miles on this weekend heading up north to give it a good test . Have a safe weekend everyone!

[LMITOUT]

I found this with a quick search and it describes both clunks, one is driveshaft related and the being other drivetrain slack.

There's been an updated technical service bulletin issued by GM with regard to the ever-popular drivetrain clunk. This one, TSB #01-04-17-004A, includes more vehicles and adds a few diagnostic tips to the previous bulletin. The original instructed replacement of the rear driveshaft slip yoke. But this modified nickel-plated slip yoke was to repair a different clunk than what you're describing--the slip yoke would stick, causing a clunk when coming to or accelerating from a stop. Your problem sounds more like the drivetrain freeplay or lash clunk when shifting gears at a stop or decelerating or accelerating quickly while driving. This condition, which GM documents as normal, is the more common complaint of GM truck owners. GM also stipulates that a lash clunk during a 2-3 upshift or 3-2 downshift also should be considered a normal non-repairable characteristic. This updated bulletin directs technicians to all clunk-related service bulletins and diagnostic procedures to eliminate any fixable cause of the noise. But there still hasn't been any repair issued to cure the freeplay clunk. You might want to mention the updated bulletin to the service-department personnel, just to make sure they've covered all the bases.

[HARPOON-OR-BUST]

I love it how they always downplay everything, "this will not adversely affect durability or performance", my A$$!! Anyway I have not noticed anything like this with my truck (2000 silverado) the problem that I was bessed with however was the start-up knock (piston slap). After argueing with GM on that one I did get a 100,000 mile warranty. Otherwise I heard the same story it won't affect the performance, I didn't buy it.

[Gus]

Quote:

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I love it how they always downplay everything, "this will not adversely affect durability or performance", my A$$!! Anyway I have not noticed anything like this with my truck (2000 silverado) the problem that I was bessed with however was the start-up knock (piston slap). After argueing with GM on that one I did get a 100,000 mile warranty. Otherwise I heard the same story it won't affect the performance, I didn't buy it.

---

Not that I want to defend GM because I think this is dump just like everyone else... but I have been reading about these problems since the probably around 98 on up. Every discussion board people say these problems are going to wreck their truck.. Well in all these years I have not once read a post saying.. Yes problem X caused my truck to die prematurely. I'm just about to start believing GM..... It still sucks though.

[burl]

Had the same problem on a 2000 3/4 ton.Brought it in to a tranny shop.They told me it was actually the torque converter.They replaced it with an aftermarket converter knowing that the gm replacement had engineering flaws.Have not had any problems since.Burl.

[MNice]

I have a 01 silverado with the dreaded clunk & piston slap. 130,000 miles w/o a problem and I don't plans on selling it anytime soon. I don't thinks it's that big of a deal.

[Hookmaster]

They aren't that big of a deal if the truck is going to last. They should be able either fix them or change the design so they don't happen.

[Blaze]

Quote:

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Simple solution...sell the chevy and buy a Ford!!! They drive till they rust apart!!!

---

Yeah...about 2.5 years!

Just kidding.

Blaze

Former Ford Driver

now gone GM

[HARPOON-OR-BUST]

It is just one of those things, you spend the money and then there is an engineering problem and they do nothing to counter it. If you think it doesn't affect anything you keep believing it.........Anyway I don't want to stray off the original post, I was just pointing out something I have heard times before. Then again GM, and the other big 3 as a whole don't make any money so why should they have to fix one of the problems they created......

[elevatorguy]

I had a 2000 half ton that had the yoke problem. It would clunk leaving from a stop. Chevy has a fix for this and they did fix it. It showed up with only 20,000 miles and they fixed no qestions asked. After they fixed I drove it for another 50,000 and it ran great. Now I have a 2003 3/4 ton with 135,000 that makes all kinds of racket when it is cold. But it quiets down and is smooth when it warms up. I had someone tell me that it is normal just something with the material the block is made of causes this. As for me I will keep driving chevys.

[walleyeaddict]

Anyone gone gm should contemplate psychiatric eval... I would not own a gm product if I won it poor craftmanship..company bordering bankruptcy..resale value no higher then anything else..despite the commmercials which where i went to school was called false advertising...FORD:::::Then DODGE:::GM fell too 3rd about 5 yrs ago!!!

[Macgyver55]

After being a mechanic for 30 years (on no particular brand)I like to read and chuckle about remarks like that. Sounds like you are a real expert.....hehehe not!

[walleyeaddict]

I get to see both perform! My pesonal vehicles are fords work vehicle gm and chev and the repair bills tell the story mr. mechanic. My last f150 I had for 5 yrs put 100000 miles on it and only ever changed oil..also it had 50000 on it when I got it who can complain about that!!The chev we drive for work had had heads replaced once and two trannies at 180000 and numerous sensors. We also have a gmc with 50000 having similar problems already and it is still brand new...Dont mean too mock u but times have changed Fords on top>>>period.