Take a closer look at the 2026 GMC Sierra 1500 AT4, one of the off-road-oriented trims in the Sierra 1500 lineup. This quick walkaround gives you a look at the Sierra AT4 exterior, interior, truck bed, technology and rugged design features while showing how the AT4 fits into the larger Sierra 1500 lineup. Shop our GMC Sierra 1500 AT4 inventory: tinyurl.com/2z37rcpb Questions about the Sierra 1500 AT4 or another GMC truck in stock? Call Dave Sinclair Buick-GMC at (314) 842-4200. Shop new GMC Sierra trucks in St. Louis, Missouri at Dave Sinclair Buick-GMC. #GMCSierra #SierraAT4 #GMCAT4 #Sierra1500 #GMCTrucks New Buick & GMC Inventory: bit.ly/4dUguGq Used Cars & Trucks: bit.ly/4bV3cXD Custom Trucks & SUVs: bit.ly/4s3tKfn Contact our team: davesinclairbuickgmc.com/contactus.aspx Dave Sinclair Buick GMC is located in St. Louis, Missouri and specializes in new Buick and GMC vehicles, used cars and trucks, GMC Yukon, GMC Sierra 1500, Sierr...