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driveline clunk

46K views 25 replies 17 participants last post by  Onlyina_Chevy 
#1 ·
I have a 2011 sierra 4x4 5.3L and I have aclunk in the driveline. When I'm slowing down from say 30-40MPH and don't come to a complete stop and then hit the gas again I get a definite clunk in the driveline, Could this be the spline joint needing some lube? I hope it is just that. Also there is no clunk from a standing start only when slowing and then accelerating again. Just want to get some ideas before I have to go off to the dealer.
 
#2 ·
Tourque converter locking up, maybe?
 
#4 ·
I thought that also (excess slack/gear lash) but I'm hoping it is just the slip joint needing lubrication/grease. I can hear it and feel it but if I just barely ease into the accelerator it is fine no clunk, but that's not possible most of the time.
 
#8 ·
I have a 2000 Z71 that had the same clunk. I took it to the dealer and they said it was normal slack. Not true. Slack is when you start out from a stop and it clunks, like a train starting to move. The tranny trashed itself, and when the dealer replaced the tranny, the clunk was still there. After a few thousand miles I decided to change the tranny filter and fluid. When I dropped the pan I found 4 selenoids there. I barely touched one of the plugs to one of the rear selenoids and it fell off. I simply reconnected it properly and checked the other 3 connectors and the other rear one was also loose. The 2 in the front were ok. Long story short, no more clunk.
 
#10 ·
Note - DO NOT grease the splines on a 4x4 truck, just use ATF. If you use grease it will migrate into the transfer case and mix with the ATF and could lead to serious problems by contaminating the fluid in the transfer case. Service bulletin out on this, grease is only to be used on 2wd trucks.
 
#11 ·
Z15 said:
Note - DO NOT grease the splines on a 4x4 truck, just use ATF. If you use grease it will migrate into the transfer case and mix with the ATF and could lead to serious problems by contaminating the fluid in the transfer case. Service bulletin out on this, grease is only to be used on 2wd trucks.
Thanks... I saw the bulletin , I already tried the Dexron ATF fluid but it had no effect at all..
 
#12 ·
It's comforting in a perverse way that some things never change ....

My '98 has, or should I say can have, a "drive line clunk". It's apparently something just characteristic of GM vehicles. But it's really easy to fix. The clunk seems to be most prevalent on one piece driveshaft models.

What is happening is the drive shaft slip joint ....the union between the drive shaft and the transmission output shaft ...is binding up. When you stop, the rear springs wrap a bit due to the torque caused by the braking action. As the rear springs wrap, they pull the slip joint outward slightly. When you release the brakes to move off, the slip joint "hangs" just a bit. With the force of the springs (which are moving back to their normal state) and the turning of the slip joint union the driveshaft "slaps" back into the output shaft of the tranny ...causing the clunk.

To fix the problem you first need to remove the rear diveshaft. Make sure you put some index markings on the junction at the rear universal so you can reinstall as it was from the factory. Put a catch pan under the tranny output/slip joint juncture ...some fluid may come out.

There is a rubber bumper inserted and bottomed into the driveshaft slip yoke (it's just a simple rubber disc) and this may or may not be installed in your slip joint. I got my little bumper at the GMC dealer ...and all the parts counter guys knew exactly what I was talking about with the clunk.

Next, thoroughly clean the slip joint of old grease and also the output shaft. The grease I used was a waterproof grease ...actually a product used for motorcycle bearings. I used it because it is very thick and doesn't thin out as it gets warm. Slather the inside of the cleaned slip joint with grease. Put a light coating on the outside. Put some grease on the end of the output shaft. Clean the rear lip seal on the tranny and give it a light coat of grease. Reinstall the driveshaft making sure to get your alignment marks squared away.

There are online postings regarding this situation (that's how I learned of it) and GM probably has a TSB out there on it. I have not had any problems with my transmission by using grease on the slip joint; the reason it clunks is because it is running dry.

You should be experiencing clunk-free driving. If you do this procedure maybe twice a year, you'll banish the clunk from your truck.

Hope this helps.
 
#13 ·
Thank's, I have the updated TSB and GM says you can no longer use grease on the slip joint only ATF so I tried it, it was no help at all. From what I'm reading on different forums it may be just the way the new 6 speed tranny shifts and possibly the programming of it.. My truck is fine when I come to a stop and on takoff from a complete stop, it is in between slowing and the accelerating again.. My 1996 and 2001 Gm trucks had the slip joint lube issue, wish that was the problem now as it is an easy temporary fix.. I'm learning to live with it.
 
#14 ·
My dad had an '04 Chevy z71 5.3L that had a driveline clunk. If I remember correctly it had a 4 speed tranny. He only had the truck for a couple of years and the clunk was present the entire time. It sounds like this could be an issue that has been around for quite a while. Does anyone know if this clunk is causing any other long term problems? If there are parts binding it can't be good for transmission seals and such.
 
#15 ·
I recently took my 08 sierra all terrain into the dealer for this exact issue.. as i slow down to make a turn and then gently accelerate, "clunk." The dealership told me that my rear universal joint, and lubricating the slip joint was the culprit. They performed the repairs, and now it is less than two weeks later, and here we have it, the clunk has survived and just as dissapointing as ever. There is no way this is just "normal" for a gm 4x4 like i have been reading online..

i have test driven many similar 4x4 z71 trucks with even more miles than my own and none of them suffered this noise.. I will be taking my truck back to a different gm dealer and hopfully turn up some results that i can share..
good luck to all!
 
#16 ·
Good luck, I am still having the same bang/clunk, it stinks, especially on a truck with only 1800 miles on it. I drove in a Ford F150 2011 5.0 liter engine 6 speed and it was fine no clunk.. I was at the dealership with my friend who is buying the Ford..
 
#17 ·
Same cirmcumstances to the clunk that I have come to live with on this particular truck; dealership seems non-plussed about this issue, even after replacing the blown rear main seal last year, and while the tranny was down, the torque converter seal and crank shaft seal....all on the 34,000 original miles I put on it from brandy new. 40,000 miles on it now, and at the dealership as I write; for what I believe is transmission problems...thank goodness for the drive train warranty.
 
#19 ·
My 2004 has two clunks. The first one was the driveshaft slip joint. I instructed the dealer about the new nickle plated front driveshaft yolk, they ordered it and put it on. Problem solved. The second clunk happens when my transmission shifts to 2nd or 3rd gear at very light throttle only. It is a normal drivline issue. GM has a bulletin on that too. They explain it as torque reversal during light throttle shifts.
 
#21 ·
schwillybo said:
i have this problem too and is also why i will not buy another chevrolet/gmc.... love my truck but after this being my third one since 2001 i am done with this crap.... a $30-$40k truck that clunks around and they cant figure it out, ill buy a tundra
Interesting. Good luck with that.
 
#22 ·
I have the clunk, first chevy out of 3 that ive ever had the problem with, im going to see what the dealer says about it, if not, i have a warranty, so if they dont want to fix it now, they can do it later whenever it breaks. I love my chevy trucks, and if i was a bit more mechanically inclined id get down there and do some of the stuff you guys have been saying, but i'd end up ruining something, so ill just deal with it, its not the end of the world to me.
 
#23 ·
Newer trucks with AFM, 6-sp trans and drive-by-wire are different that what you are probably used to. The drive-by-wire especially with 6-sp many can't get used to it. I admit when I got my 09 CTS4 I felt the same way. But after time you get used to driving it and the noises you hear now will probably be a thing of the past. Hang in there.

I have had many trucks over the years and lots strange noises from the drive train are common especially in 4x4 truck with some many interacting components. Never had a problem though, its often just noise that cannot be eliminated or avoided.
 
#24 ·
It's your slip yoke forsure take it out use proper high pressure grease put it back in and you'll be good to go prepare to do this for as long as you own your truck and as for useing ATF to do it don't or else you'll be doing it every weekend I've bin doing this for 3 yrs now never had s problem with grease mixing with tcase ATF
 
#25 ·
i have the same problem on my used '08. did anybody come up with a solution? im going to service the tranny, transfer case and rear end this week in hopes to fix this noise. btw my '07 ltz 4x4 did not ever make this noise.
 
#26 ·
Had the clunk noise in my 2000 z71....dealership said it was normal, so I dismissed the problem and drove it for another 4 years till I totaled the truck...then I didn't hear the noise anymore.

I might add, once I added the HyperTech Power Programmer and changed the shift firmness, it seemed to have reduced the clunking sound.
 

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