Rear diff whine

[JonnyDerv]

Morning guys,

Very long time since I was around these forums!
So I’m a motor trader and I’ve recently picked up a 2008 Audi S3 108k.
Drove it properly over the weekend, have to say the chassis is a huge improvement on the 8L!
Anyway I’ve noticed a whine coming from the rear diff at around 80 mph. Now this concerns me as I had a diff go on my 8L (although it was way worse than this). However there is no paper work for the haldex ever being serviced.
I’m wary as to whether it’s actually more likely to be a knackered diff than just needing a service what are peoples opinions?
The whine is only noticeable at high speed, worse with throttle input.
I can get the haldex serviced and see if it goes but the issue is the car already has a long list of work needing doing and a replacement diff is really going to put me in the red so I’m wondering if it’s even worth it and cutting my loses now while they’re minor and moving it on in trade.
Any help is much appreciated thanks!

 

[Orange225]

Could be the donuts have perished, my a3 was whining at speed and front and rear donuts sorted it, I think they’re pretty easy to check for play, Audi will tell you on facelift models they need a whole prop but you can use the reg of a prefacelift and get donuts separate

 

[dave_beastttt]

Could be the tyres, try swapping the fronts to the back and see if there's any difference

 

[JonnyDerv]

Thanks for the replies. The tyres are all brand new Falkens and they’re the same all round.
I think it’s probably worth getting it looked at and see if it’s definitely the diff. The only gen 2 ones on eBay I’ve seen are from Lithuania, all seem to be gen 4 on there for some reason which is a pain.

 

[Daveyonthemove]

Speak to Haldex repairs, they are very knowledgeable and would be able to advise and provide service parts if needed.

 

[aqibi2000]

There are additives available for about £20 for stopping diffs wining, very popular on classic cars

 

[ab1702]

A gen 2 is a haldex unit. A whining diff is a different thing altogether. From what I gather the whining is usually a diff issue though and not haldex