This started the other day and I thought I had a rock caught in my brake caliper. Well after a day or so it got worse. As of last night it started out as a sqeaky clicking noise as you started off the light and got faster as you increased speed. I put the truck in neutral a few times just to see if it would stop and it would not. This is my second Titan. It is a 2010 Pro4X with 26,000 miles. I had a 04 which I put 105,000 on before I sold it and had no rear diff problems. Does this sound like I am about to have a rear diff failure?