: "Clunk" oh now I get it! But is there a fix?



rgd
03-10-06, 02:29 AM
Early on I thought I had the clunk, it turns out that was not the clunk it was the clank! My diff bolt was loose, when tightened the clank went away.

So I was happy as a clam! I drove at least 20k miles saying to myself, "what the hell, either I'm one of the lucky ones or there are allot of V owners that don't know how to drive a 6 speed".

Now I'm neither one because after my last track day I came face to face with, "the clunk"!

Now about the question, is there a fix?

This may seem like a stupid ass thought so I want to explain were it came from. I picked up The Executive VP of one of the companies I sell for. Electronics, I'm a rep. Anyway I have known this guy for at least five years; he has a Masters from Harvard. Down to earth guy, not full of BS has a great deal of common sense. So his story seems like it might be factual, you never know.

Here it is, he hears the clunk and comments how he didn't notice that before. Then he says he owns a Denali and he has had the same problem with it for years. He also said there is a temp fix. He said he takes it into the dealer whenever it gets bad and they do the following. They open the diff case and shove a big super ball in it;yep thatís it. Somehow the super ball caused the slack to lessen or not be as drastic (not sure how to explain) but I can understand the concept. I donít know if we have the same problem and it sounds crazy but????? He said he has taken it in 5 or 6 times. I guess the super ball slowly gets chewed up until it needs cleaned out and replaced.

Any thoughts?

tedcmiller
03-10-06, 09:47 AM
What is a super ball???

nikon
03-10-06, 09:58 AM
superball? I had a 4x4 tahoe, the clunk from those things, same as the denali, espcially being 4wd is from a loose driveline, the clunk only happens when it's put into gear, everything starts to tighten up then the last thing has a lot of pressure built up on it, and clunk...it's normal on the full size trucks, do some searching one of the guys on here lifted the car put the park brake on, and did a little experiment, he said you could see the diff clunking back and forth....theres alot of rubber in the drive line, so I can understand that.....I think the superball is to just shut your friend up.

obzidian
03-10-06, 12:04 PM
ok, what is a super ball again? when i first read it, my initial thought was a football from the grandaddy of all football games....

Koooop
03-10-06, 01:05 PM
ok, what is a super ball again? when i first read it, my initial thought was a football from the grandaddy of all football games....

Pull out your Ball Gag... Look closely...

obzidian
03-10-06, 02:22 PM
Wtf?

ace996
03-10-06, 07:38 PM
A superball is one of those really hard-rubber balls, quite small...like a golf-ball, that one can bounce a few stories high, depending on how hard they can throw it to the ground.

I understand how this could work, but we'd need to drill a hole in it and then fit it over the current bushing, then jam it all inside the bushing hole.

I have no doubt that taking the bushing out, cutting the rubber off of the metal sleve and then coating the sleve with a stiffer poly-urethane would make a more durable/less flexable diff-bushing. However, it also may transmit more gear noise/whine to the passenger compartment.

I can't believe someone (listening StealthV???) hasn't taken this on and provided an aftermarket piece with polyurethane.
-ace

DgtalPimp
03-10-06, 07:42 PM
The "clunk" (not to be confused with "clank") is the driveline hitting the bottom of the car body (look for witness marks near the very back of the driveline, about a foot away from the rear diff). The upper bushing is a non-serviceable bushing on the rear diff, and this bushing goes bad from wheel hop (so I am told), so Caddy replaces the whole rear diff because of this bushing (I am on my third rear diff).

CVP33
03-10-06, 07:45 PM
Silly putty. It cures the creak, the groan, the clank, the clunk and the hop. You heard it here first! :thumbsup: Damned ass monkies. :bigroll:

Barak
03-10-06, 10:01 PM
The "clunk" (not to be confused with "clank") is the driveline hitting the bottom of the car body (look for witness marks near the very back of the driveline, about a foot away from the rear diff). The upper bushing is a non-serviceable bushing on the rear diff, and this bushing goes bad from wheel hop (so I am told), so Caddy replaces the whole rear diff because of this bushing (I am on my third rear diff).

:confused:

CTSV05
03-11-06, 12:18 AM
MMmmmm...I have no clunk...but then I have a kit....:)

ace996
03-11-06, 12:38 AM
The kit...yes...the force is strong in the kit...

wicked v
03-11-06, 01:01 AM
My clunk got worse. I took it to the dealer and they told me they replaced the differential bushings (not the cradle bushings). I picked it up today and it drives like new!

V-SATX
03-11-06, 02:23 AM
I had my V in for the clunk issue again at 2.7k and she was crying for fresh MOBIL 1 and a tire rotation. The senior mechanic explained what he thought was happening. Interesting enough, to validate his point, he pulled a new Black on Black 06 with 14 miles on it up front for us to test drive. Before we got out of the dealership parking lot I simulated the clunk twice with off RPM shifting (shifting less than optimal engine rev). I did notice the clutch seemed a bit more predictable but the same clunk with off RPM shifts. :bigroll:

Texan V
03-11-06, 06:16 AM
The "clunk" (not to be confused with "clank") is the driveline hitting the bottom of the car body (look for witness marks near the very back of the driveline, about a foot away from the rear diff). The upper bushing is a non-serviceable bushing on the rear diff, and this bushing goes bad from wheel hop (so I am told), so Caddy replaces the whole rear diff because of this bushing (I am on my third rear diff).



Not serviceable???

If that were true I wouldn't think that you could buy just the bushing...

It's not easy to replace, that much is true, as the bushing is press fit into the differential. I bought the bushing from GMPD for $9 and swapped it myself. Totally got rid of the clunk. Getting the bushing out was a bitch but worth the trouble to me as it totally eliminated clunk that had gotten progressively worse in the weeks proceeding. The rubber was all but disintegrated so the hard part was getting the thin metal sleeve out without tearing up the surrounding aluminum of the diff. I got it out with a combination of a hack saw blade and an air chisel. Cutting through the sleeve with the saw blade so that I could collapse it enough to punch it out with the air chisel. Then I dressed up the diff with a sand paper roll on a dremel before installing the new bushing with the aid of a rubber mallet.

This is something that will continue to wear out over time and need to be replaced (probably every 15k or so, based on my experience). It would be nice if a higher durometer elastomer bushing is available by the next time mine needs replacing.

CVP33
03-11-06, 06:25 AM
Not serviceable? Just blow the differential then everything is serviceable. Damn, now everyone knows my secret.

V-SATX
03-11-06, 11:04 AM
Not serviceable???

If that were true I wouldn't think that you could buy just the bushing...

It's not easy to replace, that much is true, as the bushing is press fit into the differential. I bought the bushing from GMPD for $9 and swapped it myself. Totally got rid of the clunk. Getting the bushing out was a bitch but worth the trouble to me as it totally eliminated clunk that had gotten progressively worse in the weeks proceeding. The rubber was all but disintegrated so the hard part was getting the thin metal sleeve out without tearing up the surrounding aluminum of the diff. I got it out with a combination of a hack saw blade and an air chisel. Cutting through the sleeve with the saw blade so that I could collapse it enough to punch it out with the air chisel. Then I dressed up the diff with a sand paper roll on a dremel before installing the new bushing with the aid of a rubber mallet.

This is something that will continue to wear out over time and need to be replaced (probably every 15k or so, based on my experience). It would be nice if a higher durometer elastomer bushing is available by the next time mine needs replacing.

According to your statement the stock bushing must be inferior. Especially since I drove an 06 with 14 miles; the clunk sounded no different than my 05 with 2.7K. If the fix only lasts 15k then the problem is much deeper somewhere in the driveline.

Thank you for the good information.

trekster
03-11-06, 11:16 AM
My car clunks whenever I press the clutch the morning each time i'm going to start my car.

Texan V
03-11-06, 12:05 PM
With all the rubber isolation providing slop through out the dirvetrain, dual mass flywheel, loose cradle bolts and fast wearing bushings there are lots of opportunities for the clunk type noise to rear their ugly head.

My previous post was only in regards to the top mount isolation bushing on the differential. That was the only source of clunking my V has ever generated. Not sure about the noise as soon as you push the clutch in...Maybe I would have experienced the clutch clunk too if I'd have left the dual mass unit in longer...who knows?

Seattle CTS-V
03-11-06, 01:33 PM
My clunk used to be pretty bad. Put in the BMR pinion brace and it has been 90% better since. Now I only get it if I SLAM! in the clutch at very low RPMs.

rgd
03-11-06, 04:21 PM
Not serviceable???

If that were true I wouldn't think that you could buy just the bushing...

It's not easy to replace, that much is true, as the bushing is press fit into the differential. I bought the bushing from GMPD for $9 and swapped it myself. Totally got rid of the clunk. Getting the bushing out was a bitch but worth the trouble to me as it totally eliminated clunk that had gotten progressively worse in the weeks proceeding. The rubber was all but disintegrated so the hard part was getting the thin metal sleeve out without tearing up the surrounding aluminum of the diff. I got it out with a combination of a hack saw blade and an air chisel. Cutting through the sleeve with the saw blade so that I could collapse it enough to punch it out with the air chisel. Then I dressed up the diff with a sand paper roll on a dremel before installing the new bushing with the aid of a rubber mallet.

This is something that will continue to wear out over time and need to be replaced (probably every 15k or so, based on my experience). It would be nice if a higher durometer elastomer bushing is available by the next time mine needs replacing.

Can you post the part number for the bushing. And a brief but more detailed description of the repare. How far down did you take the diff. Did you remove the drive shaft only etc..

Thanks,
rgd

Texan V
03-12-06, 05:03 AM
P/N 89058605

That's the part number to the bushing according to an old post I dug it up from. It was $9 or close to it on GMPD.

If I recall correctly, I had the car on jack stands, the rear wheels off, exhaust removed from cats back, the drive shaft removed and the diff unbolted (3 bolts, one of which that holds the bushing you replace).

I knew I had to replace the bushing as the rubber had pretty much disentgrated a a fairly large chunk of it was hanging down. I could see that the diff was able to move up and down freely and it was this which was causing the noise.