All-wheel drive versions of Western Star 4700SB (setback front axle) come in 4x4 and 6x6 versions. The frame of a 6x6 model sits 1 inch higher than a 6x4 truck, accomplished by using a compact Cummins ISL9 diesel and an offset differential on the front driving axle that puts the driveshaft to the right of the engine. The truck has a 110-inch BBC and a 42-degree wheel cut. It has 16,000-pound-capacity front axles and 40,000-pound rears. It can be spec’d with half-inch-thick, 3.2-million-RBM single-channel frame rails that weigh less than reinforced rails and avoid between-channel corrosion. The Cummins ISL can be rated up to 380 horsepower and 1,300 lb.-ft., and can be mated to an Allison 3000-series automatic transmission. The engine can also be specified with front or rear power take off.