Today in WW II: 2 Jul 1941 Empire of Japan mobilizes, calling 1 million men for military service.  

GMC M221 Truck, Tractor, 2 1/2 ton, 6x6 (G-749)

The M-221 2 1/2 Ton 6x6 Tractor is part of the GMC M-135 Series of Cargo Trucks. More information is found on the linked page.

U.S. Military GMC M221 Truck, Tractor, 2 1/2 ton, 6x6 (G-749), from TM 9-8024
U.S. Military GMC M221 Truck, Tractor, 2 1/2 ton, 6x6 (G-749), from TM 9-8024

U.S. Military GMC M221 Truck, Tractor, 2 1/2 ton, 6x6 (G-749), from TM 9-8024
U.S. Military GMC M221 Truck, Tractor, 2 1/2 ton, 6x6 (G-749), from TM 9-8024