I have a 04' F250 4WD 5.4 litre. I have this grinding feeling either mid to rear area of the truck when I am turning and throttleing at low speed the same time. I changed pads and calipers in the rear and pads on the front. Shaft seems tight and no sloppiness in the u-joints. no slipping or grinding in tranny. Any one ever heard of this?

 

Do you have the posi rear axle? Thats most likely it if you do.