Don't mind our davesinclaircustoms crew. They're just preparing to customize a 2021 GMC Sierra AT4 with the 3.0L TurboDiesel. Carry on. #gmcsierra1500 #gmcsierra1500at4 #gmcsierradiesel #gmcsierra1500denali #2021gmcsierraat4 #gmcat4 #customtrucks #liftedtrucks #duramax #gmcduramax