I was driving down the highway at a cruising speed of 60 mph when I heard a really loud bang. At first I thought I got a flat tire, but I wasn't sure so I kept going. About 10 seconds later I heard another loud bang, looked in the rear mirror and saw a small black piece fly back. I pulled over and looked the truck around and saw nothing missing or any visible damage except for a few scuff marks near the rear passenger tire and on the tire itself. I don't know if those marks were there before or if the tire marks were made when I pulled over, but I drove the rest of the way home (5 minutes away) without problem. I don't know if I could say I hit something because I didn't see anything; it was during the day and with moving traffic. If I did hit something, then it must have gotten hung up long enough to make that second bang. I don't know if anyone could share to spread light on this. The truck has about 5,000 miles on it, and I really hope this isn't a drivetrain issue.