I have a 2011 RAV4, V6, 4WD, bought used this year, now has 72k miles. The manual says to use for the transfer case and rear diff GL-5 SAE 80W-90 oil (0.48 qts).
I did a drain and filled with Super Tech 75W-90 Full Synthetic, just to see if it makes a difference. The light whine that I was...