2004 F-150 Supercrew Truck

My truck is on 80000 miles and I am feeling and hearing a nobby tires running on pavement noise like but it is not the tires. I rotated and balanced them twice from 0 to about 10000 miles. The noise is parallel to the speed of the truck. It is limitted slip differential. Where is that noise coming from?

I had a similar noise on my 2000 Blazer, it turned out to be the front wheel bearings not the tires. If the noise changes in pitch or volume when the steering wheel is turned off center (i.e. changing lanes), that is a sign of bad wheel bearings.

Ed B.