According to the rumors, the regular AT4, tagged as equipment group 4SB, will be joined by the AT4X as equipment group 4SG. Absolutely no other details have emerged, but we expect to see larger tires, DSSV dampers, unique badges, and possibly an all-black theme. Underbody protection and perhaps a unique front fascia could feature too, while the interior will likely boast more technology and luxury. Of course, these changes will look especially attractive with the 2022 Sierra about to be refreshed with new looks, a revamped interior, and more advanced driver assistance tech. That said, the AT4X may yet be applied to the older design, as the 2022 Sierra 1500 Limited is expected to be a stop-gap before the fully refreshed model arrives.