Can you see if anything is stuck under the truck? What type of rubbing sound do you hear? metallic by any chance? Does it change depending on your speed? Does it sound like a whining noise at all?
You may want to have a good shop look it over if you can't isolate the noise
I have this same noise on an 04 Dodge Ram with 5.7. Sounds like rubber "gripping" on really smooth concrete. SCUFF...SCUFF...SCUFF! It is driving me nuts!! Mine doesn't do it if you put it in neutral and coast, but does it under any amount of acceleration. It also doesn't start doing it until the truck has been operated for about 5 minutes. Seems to be of the frequency of the drive shaft rotation. Don't see anything obvious! You figure out what yours was? Truck runs great otherwise with 114k. Perplexed in Houston.