I went out at lunch and had somebody drive my truck while I walked along side and the sound is like a whimpering sound. It sounds like a bad inside brake pad, but you would think when the brake is applied it would go away? I checked the lugs and they were tight. Oh well I will put the truck up on four jack stands tomorrow and take off the left front tire and put it in 4 wheel and let her idle. I should be able to find the problem, I hope.