18309 - Customer Satisfaction Program. Certain 2019 model year Chevrolet Silverado and GMC Sierra vehicles may have a condition where the prop shaft bolts may not have been properly torqued to the front differential. Drivers will likely experience a vibration or clunking noise as the bolt(s) loosen when the vehicle is used in 4WD mode. If the vehicle continues to be driven after the vibration or clunking noise occurs, all bolts may eventually fracture. Remove front prop shaft bolts, add Loctite, and reinstall.
