The combat "N Series" were the first military 6x6 trucks by Mack. The Mack NO was designed as a prime mover for heavy artillery, with a soft top cab for a five man crew. The models NO-1 through NO-7, starting in 1943 with total production about 2000.
A Gar Wood 5MB 40,000 lb. winch was mounted in front and a hoist was mounted at the rear of the bed as a power assist for joining the gun trails of the towed artillery. The cargo body was made of wood.
The huge Mack NO 7 1/2 Ton 6x6 Truck (G532) weighed almost 30,000 lbs empty, could load another 10 tons and pull 25 tons. It was powered by the Mack EY 6 cyl. 707 cid engine with 159hp@2100rpm and 534ft-lb of torque at 800rpm. It had a 5 speed transmission mated to a two speed transfer case.