9 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHFront differential problem?
Reported or suspected cause
car's clutch
Reported cause
No successful repair reported for this finding.
1
Identified cause
0
Suspected cause
0
Reported fixes
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that report identifying a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Reported cause
Much more likely the problem is with the car's clutch.
Leading evidence: 'car's clutch' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'car's clutch' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Recommend course of action' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
(The front diff axle flange seals on my Turbo developed a leak at around 115K miles, which were replaced by a tech, but the diff was and still is ok.)
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
My info is they get replaced when they are noisy -- this is for cars under warranty -- but the noise is present when the car is moving down the road.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause
Much more likely the problem is with the car's clutch.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
9 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T205155Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Hello folks...long time no talk....
Anyway since a couple of months, i can hear like a slippery belt sound comming from the front when i release the clutch....?
i can hear the sound only when the car as been used for an hour or more...when i just start the car at the morning,,,no sound at all.
I i am in a traffic jam for example i can hear this sound just once in a while...maybe one or two times ...other then that when i just drive the car on highway no sound and no problem at all.Also no problem at all on deceleration.
I also replaced the differential oil last week with no difference.
Any idea? could it be the front differential?
Thanks
2000 C4
Doesn't really read like a front diff problem. My info is they get replaced when they are noisy -- this is for cars under warranty -- but the noise is present when the car is moving down the road.
You changed the diff fluid recently. What was the condition of the old fluid?
If you can drive the car fully warmed up down the road at various speeds and when safe to do so while weaving and not hear any noises from the front of the car the odds are the diff is ok. A thorough inspection of the front diff for any leaks is also a good idea. (The front diff axle flange seals on my Turbo developed a leak at around 115K miles, which were replaced by a tech, but the diff was and still is ok.)
Much more likely the problem is with the car's clutch. I note your car is a 2004. Is it used? What do you know about the history/usage of the car prior to your owning it, or if you are the original owner since you bought the car?
It could be your front differential. Mine sounded like a slipping belt before it failed, particularly noticable when decelerating. You don't notice it when decelerating, so it might be something different.
You have a couple of options if it's your front differential:
1. Replace it with a new differential. This is typically the dealer's recommended course of action. The part alone is roughly $7,000.
2. Replace it with a used differential. Many options are available either through salvage yards or from people who have removed their front differential to convert their vehicle to RWD. Lots of 996 turbo owners make this conversion and some C4S owners do too. This will cost you roughly half as much as a new one. Sometimes you can get a warranty if you buy one from a salvage yard.
3. Have your differential rebuilt. If you have a competent independent mechanic who can find the parts, then this is a good option. This is the route that I chose. All my bearings, the viscous coupling, etc. were replaced. This option was about $3,500 total. I like it because essentially everything is new except the case.
4. Convert your car to RWD by removing the front differential and drive components. This is the least expensive option, it's fairly easy to do and it's reversible. Obviously you lose your AWD capabilities, but it might be a good option.
Good luck!
And you likewise.
I would not think the diff would make the noise as described but your's did so there's that.
Thus I think to the OP it is clear he needs to get the car to a qualified tech for a listen. One of us (maybe) is probably right, but even so the car won't fix itself. And a front diff rebuild or replacement is not generally a job for the DIY'er car owner, though of course there are exceptions.
Definitely worth a trip to the mechanic.
Mine started making noise and leaking around the same time. The first thing I noticed was a few drops of oil on the garage near the front of the vehicle. Then I noticed the noise.
It took my mechanic quite a while to find all the parts necessary to rebuild the differential. Several parts had to be ordered from Germany. I think the car was out of service for about 10 days. Upon disassembly, the mechanic found that two of the ball bearing cages had come apart and there were a few loose pieces inside the case.
My 04 C4S Cab had the front diff replaced at 72k.
I noticed it after a spirited drive on the canyons.
Sounded like a slipping belt, was really
noticeable when decelerating for example from 4k rpm to 2k rpm in 3rd gear. Like a whine that increased its volume while decelerating.
They (OPC) raised the car (lift), put it in 2nd gear and had a tech under the car while the wheels were turning.
They told me I could still drive the car but it would get noisier (its a really annoying whine).
No leaks.
4,5k €uros.
CS
You can easily remove the front driveshaft and test on jack stands. You will quickly have your answer. I would hate to think I had to run to a "tech" everytime I heard a noise. Kind of takes the fun out of owning the 996.
