2000, C4, Cardan, Guibo Noise?

[dspeaks1165]

Hi Guys,

I am a new member.

I have been stumped trying locate a vibrating noise (that lasts approx 2-3 seconds) that my Carrerra 4 makes under load @1500-2000 rpm that's driving me nuts! As soon as the rpms get above 2000 rpm it goes away. The best I can describe the noise as the noise you would hear if the was a loose shroud with something, like a driveshaft rubbing against it. I can't produce the noise while standing still, I have to be moving. At first, I thought it was the exhaust, I have since eliminated it as the culprit. The noise comes from under the car (can't tell if its front or back) . I have checked the spark plug covers and the heat shields as well. CVs are good and so are the wheel bearings.

I have looked at every post regarding "noises" on this and every other forum on the net and my best guess is the flex/guibo connecting the cardan shaft. However, I can't find in any of the posts how to go about inspecting the Guibos on the car.

Could somebody help me shed some light please?

I recently changed the transmission mount, engine mounts, new IMS and new RMS.

Thanks in advance for any help.

[dspeaks1165]

By the way, the noise is not affecting the performance of the car...its running great.

[fpb111]

Check out this thread. The coupling is for sale for ~ $90

http://www.renntech.org/forums/topic/36862-cardan-shaft-rubber-bushing/

http://www.koperform...-Flex-Disc.html2002 Porsche Carrera, C/4 (996) >> Drive Shafts, Axles, Differentials > Driveshaft Flex DiscMake & Model Search...Below are the results for: Porsche >> 2002 >> Carrera, C/4 (996) >> Drive Shafts, Axles, Differentials >> Driveshaft Flex DiscSelect your Make:

...Porsche

Select your Year:

...2002

Select your Model:

...911 Turbo (996 Turbo)BoxsterBoxster SCarrera, C/4 (996)

Select Part Group:

... Drive Shafts, Axles,

Select Part Category:

Driveshaft Flex DiscFlex Disc -Part Search Results...Part number: 10 2539 005 options include...Item # < 1 > Qty Part #: 102539005-57 KO Price: $84.06 Shipping: $0.00 - FREE Shipping! - & *Ship Group Stock Status: In Stock - Ready to Ship!

[dspeaks1165]

I appreciate the reply and links. However, I am still trying to make sure that the Guibo is the culprit. Can you tell me how to access the Guibo for inspection.

Do you think I am on the right track?

[JFP in PA]

I appreciate the reply and links. However, I am still trying to make sure that the Guibo is the culprit. Can you tell me how to access the Guibo for inspection.

Do you think I am on the right track?

Not overly complicated; remove the plastic underbody shields, support the transmission and remove the trans mount support bolts. Remove the trans support metal brace. At this point you should be able to see the driveshaft flex disc, remove the bolts in the disc and pull the driveshaft out while putting something under the front diff to catch any oil that may drip.

This procedure, by-the-by, is fully covered in the Bentley 996 service manual with photos and complete diagrams of the components.

[dspeaks1165]

Thanks JFP ! I was hoping that that was the case. Sounds like a piece of cake. I have friend with a lift I am going to see Friday. I hope its the flex disk....its a really irritating noise.

I will let the board know the outcome.

Cheers!

[fpb111]

What was it?

[dspeaks1165]

It looks like its the cooling tubes running down the middle of the car... vibrating. One, is missing a "u" bracket. I had to special order.

The flex disk looks like it could use replacing. It will be next, If this noise doesn't disappear with the new brackets. I will post the results.

[kent996]

i replaced my flex disk with the ebay one a year ago. nice quality.

http://www.ebay.com/itm/300712978896?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1558.l2649

[dspeaks1165]

Thanks Kent, Its ordered. I replaced the broken bracket...no change.I will let the board know if changing the flex disk resolves the annoying vibration noise.

[barlowdo]

DSspeaks, A fellow Porsche owner pointed me out to this page. I have had almost the same experience with my 2001 996 C4 with Tip. It has just under 60k on it.

Here is a link that I put out on Rennlist awhile back that includes a sound file. http://forums.rennlist.com/rennforums/996-forum/729114-noise-from-right-rear.html

To me the sound is like rubbing the teeth of a hacksaw over a loose piece of sheet metal. And always under 2k - almost like a break point.

I had a person ride shotgun and listen for the sound and I could barely get the car to make the sound for him. Seems to be weight distribution enters into the equation.

I have heard the shaft goes on the Cayennes so it probably can go on the C4's also assuming of course it is the same part or of similar design.

Looks like it is time to get my car in the air and check this part out.

-Don