Hi all. I’m also experiencing the same problem or sound on my Gen.4. It only started on about 80 000km and I was also worried that it was something major. I noted that it is audible only when the vehicle is warm and when I do longish distance drives; don’t really hear it when driving in town. I did take it to the dealers but according to them, there was no strange sound when they tested the vehicle, same with a bearing noise on the rear left wheel, they recon it is the tyre making the noise.
Will be taking it back in next week for the bearing.
Had the same on my Gen 3 with 220k on the clock...was the nuts holding in the halfshafts. Went in for a service. All fine now. 