996 C4 Transmission whine - what's the best way to identify?

[Lightweight996]

My C4 had a whine from the front diff which turned out to be the prop shaft carrier bearing. In the C4 it's in the front diff housing, but easy and cheap to replace. I had the diff out for other work (seals, oil, seized drain plug) so the shop charged ~70€ for the bearing and an hours labor to change it.

Fingers crossed it's that. Its hard to hear exactly where it's coming from, it seems loudest around the gear stick area.

 

[Alex]

The 70 euro was on top of the big bill to remove and refit the diff.

 

[Lightweight996]

The 70 euro was on top of the big bill to remove and refit the diff.

I haven't looked into it, but is the front diff a hard job to remove?

I've done a fair bit of work on many cars over the years (auto to manual conversions, engine swaps, supercharging etc.) so confident tackling most things, only if I have the time though.

 

[Alex]

You need to identify if there's a fault and where its coming from first.

 

[deMort]

In the video it doesn't sound that loud .. if the position is gearstick area though then front diff is the most obvious .. i need to have a listen to the car really to say if normal or its diff bearings .

Rough cost on diff bearing replacement is around £850 though ... thats down south where the costs are indeed higher .

 

[Lightweight996]

Thanks deMort, good to know, I'll arrange to pop down your way soon.

All the help is really appreciated! Where would we be without forums eh!

 

[GMG]

...we are lucky as we have Iain supporting this wonderful forum :thumbs:

 

[ScoobyDoo555]

I think I have a similar issue with my front diff - I'll record it for submission to the forum - might help others in future.

The sound is certainly from the front. It's not affecting performance though (until it does and borks the diff!)

Can't really complain as the car's now done 123k (miles). Kind of expected imho.

Got some other issues to fix first, then I'll probably get it into a "local" place (the nearest being 50 mile away)

Would be interested to compare videos etc though

Dan

 

[Lightweight996]

Although it sounded like it was loudest near the front mine's definitely not the front diff as I have removed all the 4wd bits now and it's still whining. It's currently on the "I really should sort this" list.

 

[mashby]

My brothers C4s was making a similar whining noise. Fearing the worst he took it to our indy and he mentioned it could be tyre noise. It was on 5 year old P Zeros.
Thought it worth a try and put a new set of Pilot Sports on. The whining disappeared straight away.
Might not be your problem but if you could try a different set of wheels/tyres to rule it out.

 

[ScoobyDoo555]

TBF, I had the wheels refurbed and brand new rubber put on, so I dismissed that.

But I'm just editing it down to see if I can get a good "sound"

Dan

 

[vlad]

Another suggestion, perhaps a longshot, but many moons ago I had a whining from the front area 996 C4S, increased with speed, booked her in for fixing fully expecting it to be expensive , front diff or some such.

Turned out to be loose undertray!

 

[ScoobyDoo555]

I'm suspecting either low on fluid, or the fluid has never been changed - the car's 21 years old and by the looks of it, most of the care has been done in my possession.

Just trying to fix my power-steering at the moment - put a post in another thread.
Trying to find out how much I need.

Ideas?

Dan