Truck just rolled 100,000kms. To celebrate it got a transmission fluid exchange and new 275/70/18 BFG K02's. I thought that would solve the "tire noise" but it made it worse (actually the new tires were just quieter). Took the truck to GMC for the trans service and they noted the pinion bearing is going out. All covered by powertrain warranty. That will be the first repair required outside of a seal on the cab brake light. Some weeping on the trans cooler lines I'm keeping and eye on, and something is wrong with the fuel tank evap system. Too lazy to fix so I leave the truck running when I fuel up.