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About the clunk

21K views 29 replies 22 participants last post by  Veeksi 
#1 · (Edited)
I keep reading posts concerning the clunking noise.
Read page 16 in your "Getting to Know Your 2007 SKY" booklet.

I made a correction after being set straight by COLET 50

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#3 ·
Thanks! I guess everyone should RTFM.:lol:
 
#4 ·
My feeling on this is that it is like the "Piston Slap" that GM deemed normal...Normal? are you kidding? I guess it only has to hold for 36k miles in GMs Mind...We'll see how it plays out.
 
#5 ·
PieintheSky said:
.....
Read page 16 in your "Getting to Know Your 2007 SKY" booklet.
It happens only to cars equipped with the LSD and it is normal.
.....
No, they didn't say so.

a) the rear axle maybe equipped with a limited slip diff

b) with man. trans you can do abrupt torque transfer
(low gear shifting at low engine speed) or abrupt de-clutching.

Clunking can accure with or without a limited-slip-unit.
A bit of clunking is normal with front engine - rear wheel drive - concept combined with manual trannys. With autotrans the shifting is smoother and will be damped by the oil-filled torque converter.

The clunk can be caused by

- the gear slack (working loose) of the diff gears
- the cardan shaft (working loose in the cardan joints)
- the manual tranny gear slack/working loose of the gears.

Another point to consider is that a roadster is an "open" car, the same noise makes a louder impression than in a closed and good isolated cars.

You can test the working loose of the diff and the cardan shaft yourself:

Lift up one rear tyre a bit, block a front wheel, put a gear in, loosen emergency brake.
If you turn that lifted wheel in both directions, you may hear the clunk and you can messure the "free" angle at the wheel. If you want to know the part of the free angle caused by the diff, you have to block the cardan shaft at the entrance of the diff.
If you want you can compare this testing with a car with same driving concept witch doesn´t clunk.

I don´t want to say GM/Getrag made a good job but to decide if - at first the real reason must be found.
 
#8 · (Edited)
Clunk

Just Bought My (Chili Pepper Red + Tan) Sky On The 9th. I Noticed The Clunk As I Was Leaving The Lot, Turned Around And Went Back In The Show Room. I Was Told That Was Normal Due To The (lSD) And Sudden Clutch Disengaging. I'm Not All That Convinced! I Read The Manuel And Saw That The Clunk Was Normal.

I Bought A New Mx5 (M Edition) In '95 With The Extra Hard Top Which Also Had LSD And In All The 80,000 Miles I Never Heard A Clunk. Traded The Mx5 For A Black Toyota Celica GTS In 2000, Never Heard Any Clunks Or Rattles In The Length Of Time I Owned It (5 Years). I Also Noticed On The Window Sticker, The Sky Was Built In The USA But Had A Japanese Transmission. (Who Makes The 5 Speed Stick For The Sky?) If I'm As Pleased With The Sky As I Was With The Mx5 And Celica This Will Be One Happy Old Man.

I Just Happen To Remember I Owned A Chevy Custom Van In The 80's And Every Time I Lifted My Foot Off The Gas To Slow Down I Heard The Clunk From The Rear End. It Had A Sloppy Fit In The Grears In The Axle. I Was Told I'd Just Have To Live With It, That Was The Last US Made Car I Owned Until Now. I Hope I Didn't Make A Mistake.

At Present The Sky Will Have To Share The Garage With The Black
G-35 Coupe And The Black Pathfinder. I Ordered A Black Or Green Sky But Got Tired Of Waiting And Took The Chili Pepper Red When Offered.

The Saturn Dealer In Chatt. Tn. Is Next Door To The Pontiac Dealer Which Added An Extra $5,000 Dealer Profit To The Soltice. I Don't See How They Will Sell The Pontiac With The Sky Setting In Their Back Yard For Less Money.

All The Guys At Work Ask How Many Time A Day Do I Put That Red Sports Car Own. Either That Or Why Don't You Buy A Car Bigger Than You The Next. Lol

UTCCOP
 
#9 ·
Clunk and other problems

UTCCOP said:
Just Bought My (Chili Pepper Red + Tan) Sky On The 9th. I Noticed The Clunk As I Was Leaving The Lot, Turned Around And Went Back In The Show Room. I Was Told That Was Normal Due To The (lSD) And Sudden Clutch Disengaging. I'm Not All That Convinced! I Read The Manuel And Saw That The Clunk Was Normal.
.....
Hey Mr. COP,

at first welcome to the Kappa family.:cheers:

The "clunk" problem has been discussed here several times and even more in the SolForum, use Search.

The clunk has nothing to do with the LSD, see above.

A bit of clunking is normal but that much as is many of the Kappas occured, seems to me not normal anymore. But it should be difficult to get a repair/change under warranty, especially because there are no damages known upto now caused by the clunking.

The other problem is the leaking of the several rear ends, not so often with the Skies yet but there are numerous Sols which had/have that problem:

If I remember the discussions on SolForum there had been three problems

- wrong quality of the seal(s) (mineral oil/synthetic oil problem?)
- misfunktion of the venting valve (over pressure in the box)
- overfilled gearboxes (over pressure in the box)

Some lost too much oil and damaged the diff (changed under warranty).
The diffs are manufactured by GETRAG (German manufacturer, also delivers FORD). There is no information if it was only a starting problem and if the problem is solved now.:confused:

BTW does somebody know if the GETRAG diffs are manufactured in Newton, NC or delivered from the German plant or whereelse in the world?


UTCCOP said:
.... I Also Noticed On The Window Sticker, The Sky Was Built In The USA But Had A Japanese Transmission. (Who Makes The 5 Speed Stick For The Sky?) If I'm As Pleased With The Sky As I Was With The Mx5 And Celica This Will Be One Happy Old Man.....
The 5 speed manual tranny is manufactured by the Japanese manufacturer AISIN (60,000 employees, 11 plant worldwide).
This tranny is in use in some other US cars since several years, see list

View attachment 2007_Aisin_AR5_MA5.pdf

There are no specific problems known with that tranny up to now.

UTCCOP said:
....I Just Happen To Remember I Owned A Chevy Custom Van In The 80's And Every Time I Lifted My Foot Off The Gas To Slow Down I Heard The Clunk From The Rear End. It Had A Sloppy Fit In The Grears In The Axle. I Was Told I'd Just Have To Live With It, That Was The Last US Made Car I Owned Until Now. I Hope I Didn't Make A Mistake.
.....
UTCCOP
I don't think you made a mistake, because the Sky is a really World Car:

- base disign from Vauxhall
- base engine from Opel (Ecotec)
- tranny from AISIN
- diff from GETRAG
- suspension from Bilstein
....
Don't forget it's first year production, I'm convinced GM and his component partners will solve the starting problems in the next time. :thumbs:
 
#10 ·
Does the clunk get any better after the break-in period? We've only got about 200 miles on it so far... and it's kind of annoying me! :rolleyes:
 
#11 ·
Jen said:
Does the clunk get any better after the break-in period? We've only got about 200 miles on it so far... and it's kind of annoying me! :rolleyes:
Jen,

you should have no expectation on that, because over the years the gear slack (working loose) of the diff gears gets larger caused by normal wear and the other coponents like cardan joints and manual tranny do the same. :banghead:

I remember a method some "horse dealer" (german for deceitful car dealers) used for damping the noise of old wornout diffs: filling the diff full up with bananas then it's not as loud. Helps for some hundred miles before the diff breaks totally.

Don't do it with yours! :jester:
 
#12 ·
Heres GM's description

Subject: Information on Driveline Clunk Noise When Shifting Gears at Low Speeds #05-07-29-005A - (03/29/2006)



Models: 2006 Pontiac Solstice

2007 Saturn Sky

with AISIN AR5 Manual Transmission (RPO MA5)




--------------------------------------------------------------------------------

This bulletin is being revised to add the 2007 Sky. Please discard Corporate Bulletin Number 05-07-29-005 (Section 07 - Transmission/Transaxle).


--------------------------------------------------------------------------------

A Pontiac Solstice/Saturn Sky equipped with a manual transmission may exhibit a clunk noise when shifting gears at low speeds. The noise may be present during low speed driving maneuvers, such as driving in stop-and-go traffic or in parking lots, which require declutching and shifting.

Some amount of driveline clunk is normal due to the design characteristics of the driveline system. While some owners may find the clunk noise objectionable, it will not adversely affect durability or performance.

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 can translate into a clunk noise whenever the gears are loaded and unloaded quickly. Comments of driveline clunk are usually not the result of one individual component, but the result of clearance present in all of the driveline components.

Because all components in the driveline have a certain amount of clearance by design, changing driveline components may not result in a satisfactory noise reduction.

Initial steps should be taken to ensure that the clunk concern is not an actual component issue. Refer to the following Service Information documents for additional information and diagnosis:

• Information Bulletin-Manual Transmission Operating Characteristics -- Corporate Bulletin Number 03-07-29-004B

• Symptoms - Manual Transmission

• Transmission System Description and Operation (Solstice) or Transmission System Description and Operation (Sky)

• Transmission Clunk on Acceleration or Deceleration

• Differential -- Fastener Tightening Specifications

• Driveshaft -- Fastener Tightening Specifications

• Transmission Noisy
 
#13 ·
What the Bulletin tells to me ....

SkyTech said:
Subject: Information on Driveline Clunk Noise When Shifting Gears at Low Speeds #05-07-29-005A - (03/29/2006)

Models: 2006 Pontiac Solstice 2007 Saturn Sky

- with AISIN AR5 Manual Transmission (RPO MA5)

- and the GETRAG Differential
--------------------------------------------------------------------------------
Some amount of driveline clunk is normal due to the design characteristics of the driveline system.
That's true but the problem is how much of "some amount" !

While some owners may find the clunk noise objectionable, it will not adversely affect durability or performance.
A bit true, warranty time might be just over before durability becomes a problem.

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.
That's true but the problem is how much of "some amount" ! - same conclusion as above

Because all components in the driveline have a certain amount of clearance by design, changing driveline components may not result in a satisfactory noise reduction.
That's true, if you don't have better manufactured components with lower clearance it won't help!

Did I misunderstand anything :confused: :confused:
 
#15 ·
I had never heard the clunk, but I usually shift around 3000 rpms. A friend of my was driving the car the other day and was shifting at lower rpms and I definately could hear the clunk.
Are there any disadvantages to shifting at 3000 rpms as apposed to lower ones?
 
#16 ·
GRinLR said:
I had never heard the clunk, but I usually shift around 3000 rpms. A friend of my was driving the car the other day and was shifting at lower rpms and I definately could hear the clunk.
Are there any disadvantages to shifting at 3000 rpms as apposed to lower ones?
I have heard the clunk. But I'm like you GR, I usually shift at 3000 to 4000 RPM and I don't have a clunk problem. I do have a noisy rearend I'm going to have the dealer check out.
 
#19 ·
Diff

Its typical drivetrain lash. It also depends how you handle clutching. There is some'wind up' in a RWD driveline. Sorry to keep using the CTS-V as an example but its the same set up with the same problem. I was smooth with release of the clutch so it didnt bother me. If you put the car under load and quick release the clutch, the lash in the driveline will clunk. Its a band aid approach but smooth release before and after loading will reduce that racket. At lease the Sky has a 1 peice driveshaft.
 
#20 ·
you ought to hear the amont of noise the manual trans makes when a microphone pickup is attached to it... there is no such thing as a quiet manual trans anymore.

the majority of the clunk however is not in the trans, the differential, the differential mount bushings or any other component save one: the driveshaft.

the rear coupling attached to the differential is rubber and under torque they twist slightly. when the clutch is depressed the torque is removed and the coupling snap backs, which causes the snap noise, which yes is becuase of the buildup of driveline lash. replace this coupling with a solid one and your clunk is greatly reduced.
 
#21 ·
Clunk

I used to have a 1967 Pontiac Lemans - with a 327 or so V8 - and a 3 speed manual tranny (not a pontiac tranny I think) - and I had a really bad clunking noise when I did things like got into high torque - let of the gas - the hit the gas again. It turned out to be bad universal joints - after I replaced the UV joints - the clunk was either gone - or so slight that I could not hear it anymore. Now I would not expect a brnad new car to have bad UV joints - and I imagine the drive train of a modern car is at least a little bit more complex than those of 1967 - but it does seem odd to me that GM says clunking is normal and for the various posts on the topic this is virtually unheard of from other manufacturers.

From a general engineering principles perspective - if there is a noise there is a transfer of engergy occuring - which, over time, if not part of the design, could cause prematrue wear of the parts involved - or even sudden failure of those parts.
 
#22 ·
Searched for this topic because we have noticed this noise. Didn't hear it before because we always had the top down. Now that it's cooling off we've had the top up. I'm still having trunk/roof issues so when they look at that I'll have them take a look just to be sure it's normal. I don't hear it all the time either. Some times it's not there. Sometimes louder than other times.
 
#23 ·
Well all I gotta say is this: So far I got lucky, I inherited a previous order and it had the automatic and the regular rear end--So far after reading all these threads with the "clunking drive system, leaking LSD's, whining LSD's" I am grateful I did not buy the manual OR the LSD's for ther first 1-2 years cars being produced--I still beleive the clunking is NOT normal, and I KNOW the leaking and whining LSD's is NOT normal--:banghead: BTW, on my Sky, NO clunking, NO whining and finally NO leaking rear end----SO far-Knock on WOOD!-:D
 
#26 ·
I must have gotten lucky too. I have the LS Dif and as of this far had no leaks and have heard no Clunking sound except the first couple of times I drove it and didn't have enough RPM's and let the clutch out, I have the Manual trans and have up to this point experienced no whining sound from the differential.
The only Interesting thing I've heard from the engine is after I put the CAI on it I started hearing the Throttle plate When starting from a dead stop the ECM will throw the throttle plate wide open for a fraction of a second creating a strange sucking whoosh before the engine catches up and the ECM feathers the throttle plate back out. I assumed however that it was because it's fly by wire and they all probably do this.

I do have one major problem though any time I'm near the car I have an unremoveable Permagrin on my face:jester: :dthumbs: :D
 
#24 ·
Just wanted to say that while idling in first gear through a large dealership parking lot late at night when it is quiet (no radio) there is enough power to keep you going at a real low speed, but what a loud HUM. My Wife said what on earth is that? Are we getting ready to blast off? I said it's drive line noise. Am I on target?? Hey boys and girls, it is loud!
 
#25 ·
auto tranny

I have an auto and I even hear the clunk when I let off the gas and then hit it again it makes a noise though I'm not sure if its the same :jester:
 
#27 ·
I apologize for reviving an ancient thread, but I came up with this when I searched helped for my problem.

So I bought '07 OPEL GT (which is a Sky Redline manual with LSD for you guys). When I test-drived the car, I didn't find anything disturbing. So I made the deal and drove to my home. But then the problem occured. When reversing to my garage, (giving 1500-2000rpm and pumping the clutch) I heard this odd clunking noise. It actually happened everytime I pushed on the clutch. Wasn't just one "clunk" but "CLUNK, clunk". If I let the car cool down for a night, it's ok in the morning...no clunking at all. But as soon as the driveline warms-up, the clunking gets back.

So I visited a beemer mechanic. He was amazed about this problem. The rear-differential doesn't whine while driving, but sure gives a lot of clunking in certain situations (pushing on clutch in low speeds). And there is noticable amount of loose in differential if u lift up the car and roll the rear tires (let's say if u start rolling the driver's side rear tire, it takes about 2-4 inches after the cardane-axle starts rolling and then you hear the clunk aswell).

...so I was about to get a new rear-differential for over 3000 $ (2960 euros), but now it seems it might be normal, is it? Funny the beemers don't have this kind of problem as most of them are manual over here and have various kind of rear-differentials...
 
#28 ·
I have also bougt a 07 Opel GT with the same specs as you (but living in sweden) and have exactly the same issues. Mine have done 17000 km (not much) and i also have some kind off differential noice when turning. Took it to the dealership but unfortunatly the knowledge of theese cars is practically none here. The tech said it was normal noice, i wanted to get a review of all tech bulletins because there is one about changing the diff oil but they couldn´t find any if interest.

My genereal feeling is that the workshop have no knowledge of the car and there is definitly something weird with the drivetrain, it feels "loose". Also i thing one should remember the you are practically sitting over the rear diff and the axle is very close to you so that could be why you are hearing clunks which are not heard in f.i BMW´s. Im not so worried about the sound but i don´t like the slack in the tranny, it takes away the experience.
 
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