I have a 2014 with 203000 miles. At 150,000 it dropped an exhaust valve on the cylinder right in front of the driver. No engine damage but it did cost $1000. The only other thing is I rebuild my shocks at 130,000, then at 200,000 replaced them. Very reliable truck.
Just for clarification, it sounds more like it broke a valve spring; if a valve had dropped it would have damaged the head and piston.