flat tow

According to Remco a 2015 Sierra 1500 4WD with a 6L80 transmission and a two-speed transfer case can be 4-down towed as is, subject to the conditions listed in the owner's manual. Remco indicates there are no speed or distance limits, but for extended time tows the engine should be started periodically to keep the battery charged. The Sierra 2500 and 3500 4WD models with a 6L90 transmission are also towable with the same conditions.