I made the service manager angry and he threw a copy of the internal GM TSB for this issue at me. I will attach it when I return home from Omaha. The gist of the document says that "some" of your customers may feel a slight vibration from temporary flat spits on Goodyear times because the compound was made to decrease wear of tire at higher speeds. The document states that it will go away as tires warm up. Brand new truck and dealership says it is GMs problem. I will post actual document on Thursday.