Grant my 4/4 (2011) has had the diff “moded” to 4.1:1 & it does just that. The noise is more of a gear ringing noise. I was warned prior to fitment that they could be noisy due manufacturing tolerance. No limited slip involved. I assume yours has not been modified but maybe the same problem. I sound insulated the rear woody bits to help deaden the noise.
I agree, I was copilot in several 4.1 final drive cars. They all howl and chirp. But still, a 4.1 final drive is very sporty in a 4/4.
