Grinding when accelarating

[Christopher Dyke]

Hi just bought myself a 2000 Carrera 4 with 80k and an exceptional porsche service history. Only problem is im sometimes getting a slight grinding from the front end of the car when accelerating. I know the car has been standing for a while, just wondering if anyone has had the same sort of problem / issue?

Any advice would be greatly appreciated as the car is still under warranty if it could potentially be something serious.

[xmac]

Did you see a line item for a front differential gear oil change in the service history? I had a whine in my 99 C4 that sounded like a rally car gearbox. When I changed the fluid, what came out was almost black unlike what came out of the transmission. After replacing the gear oil, the noise went away. I would start there.

It is a 30 minute job, but the fluid is expensive, part# 999 917 546 00. Here's a nice DIY.

http://www.renntech.org/forums/tutorials/article/60-front-wheel-drive-oil-change-instructions/

[Christopher Dyke]

Thanks will give that a try first and hope its that simple a fix.

[xmac]

I thought about it some more and started wondering if it is a front wheel bearing. A bad bearing can make a "grinding" noise - easy to check. When the front wheels are up in the air, grab the bottom and top of the wheel and see if you feel movement in the wheel. This is a video of a really bad one, but the check procedure is the same:

Much more involved, but here is the bearing replacement DIY:

http://www.renntech.org/forums/tutorials/article/29-diy-front-wheel-bearing-replacement-996-ttc4gt2/

[roadsession]

Here you go:

http://www.renntech.org/forums/topic/28766-mysterious-grinding-noise-when-turning-in-my-02-996/page__p__189168__hl__grinding%20accelerating__fromsearch__1#entry189168

[Christopher Dyke]

Hi Thanks for the responses lads. So far have had the fluids changed in the car, which hasn't resolved the problem and a porsche specialist looked over bearings and everything mechanically but says all that seems fine and they cant find out whats making the noise - saying its probably a wind panel but to keep going until it gets worse so they can locate it easier. I have checked out the above link, which kinda sounds like the problem im having but the noise im getting happens in straight lines or corners always around 1500 to 2000 revs then simply goes.

The garage I have bought it from wants me to collect the car back as they say nothing mechanically can be found wrong with it (but obviously something isn't right) and I only have 30 day warranty with the car so ive got get problem resolved before then. Im thinking they have to take it to the porsche main dealer to get problem detected / resolved but they are saying the main dealers will come back as confused as the specialists (with same findings) and charge fortune in labour for the privilege.

Anyone got anymore suggestions on what problem could be ?

Thanks Again

Chris

[kent996]

if your car is automatic, then the problem should be the TCU. many pre-2003 tiptronic 996 cars have this problem.

Hi just bought myself a 2000 Carrera 4 with 80k and an exceptional porsche service history. Only problem is im sometimes getting a slight grinding from the front end of the car when accelerating. I know the car has been standing for a while, just wondering if anyone has had the same sort of problem / issue?

Any advice would be greatly appreciated as the car is still under warranty if it could potentially be something serious.

[Christopher Dyke]

Thanks kent996, so what is the fix for the TCU ? Is it expensive job ?

[kent996]

Thanks kent996, so what is the fix for the TCU ? Is it expensive job ?

Replace the old one with the updated one

[fpb111]

I know you had someone look at it. But are you/they sure it isn't the flex coupling on the cardon shaft? Porsche does not sell it separately, only the whole shaft @~$700.00. Others do offer it as stand alone part.

Driveshaft flex disc - C4 and Turbo

These folks list the OEM Porsche replacement for $75 KO Performance in Florida.

I found it in their 2004 C4 parts list.

http://www.koperformance.com/

Part #: 102539005-57

KO Price: $74.61

Shipping: $0.00 - FREE Shipping! - & *Ship Group

Stock Status: In Stock - Ready to Ship!

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

Book #: 10 2539 005

Description: Driveshaft Flex Disc

Applications: Carrera 4 99 thru 05

Manufacturer: O.E.M.

Edited December 12, 2011 by fpb111