my truck seems to run like silk, my mechanic when looking for an unknown noise, checked the rear diff fluid and found, very very minute metal particles. Now he has scared me to death with finding a replacement rear end. Truck is a 2010, and only has 63 K on it. I am thinks nag of riding it out as it is, no clunking of gears nothing that would indicate rear is shot. Can any one here shed somelight on my situation. he says he did not think it was an axle bearing, but did find caliper holding some pressure on the brakes, he put new brakes and caliper and rotor on, but says that the noise was still there, this guy is not a Toyota mechanic is there maybe something he is missing or does not know! Thanks for any help