Took the Runner to the dealership to diagnose the front end grinding that I've been experiencing the last couple of weeks, I was suspecting a bearing or seized caliper since it got worse with braking. Just got a call from the dealer and he said that it was a bearing issue in the front dif, and that it went away when you put the truck into 4WD. He said they had to run around to source some parts and gaskets, but that they were able to get everything replaced under warranty and the truck is done! Hopefully this solves the front end grinding, that shit was driving me insane!