You guys should check out my thread for my truck.......my dad purchased a Silverado with 22k miles and it rattled. Mostly at slower speeds and on rougher terrain. I borrowed his truck one day and had to pull over on the side of the road cause I am really OCD and couldnt take it. I ended up deciding that it was coming from inside the cab to my surprise........I thought for sure it was a muffled sound from the exterior. Turns out, there is a metal belly pan that covers the steering shaft. All like 6 screws (with washers) were loose......I mean LOOSE! I tightened them up and good to go. Fast forward a couple years.......I purchased a 2015 GMC Sierra 40k miles. Exact same noise, exact same issue. Tightened the bolts, no more rattle. There are some pics on my thread if you wanna check them out. Should note.......One truck was manufactured in Canada, and the other Mexico