Quattro rumbling

[Elroy Blue]

Friend has an A7 and I've noticed when manoeuvring at low speed, (such as a 90° turn into a driveway) there's a very pronounced rumbling. A bit of googling suggested it may be down to the Quattro system, but the comments found related to other models. It doesn't happen at anything above walking pace and only when turning sharply. Is it something to get concerned about, or is it in fact one of those 'they all do that' things.
It's been like that since he got it and all the tyres are evenly worn. (It's got less than 10k on it)

[Elroy Blue]

Itts very noticeable even from the passenger seat. Never experienced anything like it in other 4wd cars. As long as it's not a big bill looming outside of warranty.

[Elroy Blue]

Cheers all. That'll reassure him