The International Harvester Company, IHC, often simply referred to as “International”, originates from the merger in 1902 of the McCormick Harvesting Machine Company and Deering Harvester Company with 3 other small companies specializing in agricultural mechanical equipment. During World War II, IHC has attained the rank of 33rd supplier for the US military.
Our tractor is a “M425 – H542-9 – 5-ton truck Tractor”
M425 is the US Army classification. This type of truck was produced in two very similar versions: there was also the “M426 – H542-11” with a slightly higher tonnage.
H542-9 is the manufacturer classification.  The H is for the manufacturer (Harvester), 542 is the type and 9 refers to the tire size: 9.00×20. The M426 was referenced by IHC “H542-11”, being equipped with 11.00×20 tires. It was equipped with reinforced suspensions. The mechanical base was the same:
International Red Diamond 450D engine, 6-cylinder gasoline, 125 hp
clutch W.C. Lips, Model Z-32
transmission IHC Model F-54-D, 5 speed (5th direct)
All were COE, “cab over engine”, although the cab was not entirely over the engine, the truck having a short hood (Hayes cabin).
4,640 M425 were manufactured by IHC and 10,978  M426 were manufactured by three companies:
6,678 by IHC with IHC axles,
1,100 by Kenworth with Timken axles,
3,200 by Marmon-Herrington with Timken axles
Note that 1,200 M425 were rebuilt by Marmon-Herrington in 1945 according to M426 specifications. They were then designated H542-11-C, C for “converted”.
The M425 was associated with the 5-ton trailer. The M426 was associated with the 10-ton trailer. Both trailers were of the type “stake and platform” with one axle and dual wheels. The tires were the same as those of the tractor, ensuring identical loads on trailer axle and rear truck axle.
The short wheelbase tractor and non motorized front axle gave it an excellent turning radius, easing maneuvers with the trailer.
These trucks were a great success on the Red Ball Express logistics roads, but they were also popular on many other operations, including the blockade of Berlin shortly after the war.

Technical data

Empty weight : 12,000 lb (5,440 kg)
Payload : 12,000 lb (5,440 kg)
Length : 200² (5.07 m)
Width : 97² (2 .48 m)
Height : 105² (2.66 m)
Ground clearance : 101/2² (0.26 m)
Wheel base : 120² (3.05 m)
Gasoline tank : 80 gal (300 l)
Electrical equipment : 6 v
Air brakes
Tires : 9.00×20
Gasoline engine by IHC, modèle : H-542-9
6 cylinders in line, valve-in-head, displacement : 452 cu in (7.4 l), 143 hp at 2,600 rpm
Fuel consumption : 2.6 mpg (110 l/100 100 km)
Transmission : 4×2, 5 speed