I have exactly the same issue with my'13 GX. I reported it with just 15k miles, and dealer investigated for 3 weeks and supposedly ended up replacing the transfer case. When the car was returned, I noticed the same issue and reported it to the dealer again during next scheduled maintenance. The vehicle has been with the dealer for a month now, and they are finally calling in their regional technical expert to investigate. The dealer has mentioned that this is an issue with all GX models, including previous year and newer models. I'm not buying it. What experience have you had with your dealer? Are you considering taking any action in an attempt to receive refund? The noise is a nuisance, and I am concerned about future costly repairs and resale value.