|This article needs additional citations for verification. (May 2014)|
Restored CCKW 353 Cargo truck with open cab, machine gun ring,
and front-mounted winch.
|Place of origin||United States|
|Weight||(CCKW 353 empty) 11,250 lb (5,100 kg)|
|Length||(CCKW 353) 256 in (650 cm)|
|Width||86 in (218 cm)|
|Height||93 in (236 cm)|
|Provision for machine gun mount|
|Engine||GMC 270 269 cu in (4.4 L) gasoline I6
91.5 hp (68.2 kW)
216 lbf·ft (293 N·m)
|Speed||45 mph (72 km/h)|
Thе GMC CCKW is a 2 1⁄2 ton 6X6 U.S. Army cargo truck that saw service in World War II and the Korean War, often referred to as a "Deuce and a Half" or "Jimmy". The CCKW came in many variants, based on the open or closed cab, and Long Wheel Base (LWB 353) or Short Wheel Base (SWB 352).
CCKWs were employed in large numbers for the Red Ball Express, an enormous convoy system created by the Allies to supply their forces moving through Europe. At its peak, the Red Ball operated 5,958 vehicles, and carried about 12,500 tons of supplies a day.
- "C", designed in 1941
- "C", conventional cab
- "K", all-wheel drive
- "W", dual rear axles
Including the DUKW, General Motors in the US produced 562,750 of these 2 1⁄2 ton 2 lb (0.91 kg)trucks just prior to and during World War II.
In 1940 the US Army set a requirement for a 6x6 truck with a 12 ft (3.7 m) cargo area and a 2 1⁄2 ton (2268 kg) off-road payload. General Motors, already supplying modified commercial trucks to the Army, modified the 1939 ACKWX built for the French Army into the CCKW[a]. The General Motors design was chosen as the standard for the US Army.
In 1942 GM’s Yellow Truck and Coach Division began building CCKWs and 6x4 CCWs in Pontiac, Michigan and then at a Chevrolet plant in St. Louis, Missouri. In 1943 Yellow became GMC Truck and Coach Division, the trucks have been known as GMCs ("Jimmys") since then. By the end of production in 1945 562,750 had been built, a total second only to the “Jeep”.    
Engine and driveline
The CCKW had a gasoline 270 cu in (4.4 L) in inline 6 with 91 hp (68 kW) at 2750rpm and 216 lbf·ft (293 N·m) at 1400rpm. This overhead valve engine was designed for commercial trucks, and proved strong and reliable in service. A 5 speed transmission drove a 2 speed transfer case, which also selectively engaged and disengaged the front axle drive. Early trucks used vendor axles, later GMC also began making their own axles for many trucks.
The chassis was built in two wheelbases, the short Model 352 and the long Model 353. The short, 145 in (368 cm) / 167 in (424 cm)[b], was used, with a short cargo bed, as an artillery prime mover for 75mm and 105mm howitzers. All other models used the long, 164 in (417 cm) / 186 in (472 cm).[b] Tires were 7.50-20, brakes were hydraulic with vacuum assist.
Some had 10,000 lb (4,500 kg) front mounted winches. These used longer frame rails, and could only be installed at the factory, not in the field.
Initially all versions used a modified commercial closed cab design having a metal roof and doors. By 1944 an open cab version, with a canvas roof and doors, was used. This was easier to build, and the roof could be removed to lower the shipping height. 1 in 4 open cabs had a machine gun mounting ring above the co-drivers position.
No other US vehicle had a wider range of bodies, the 12 ft (3.7 m) cargo version was by far the most common. During production the steel cargo bed was replaced by a wooden one to conserve steel. Wooded beds proved unsatisfactory and a 'composite' bed with steel sides, framing, and wooden slats was developed. The composite bed was eventually replaced with an all-steel bed.
The body with the most variations was a rectangular van. This was used in communications, medical, workshop, and many other specialty roles. The main difference that can be seen is the number and type of windows along the top of the box.
In addition to the two major types, many other bodies were built in smaller numbers, and others were converted in the field. The CCKW performed near countless duties, some were:
- Truck, cargo, 2½-Ton, 6X6, long-wheelbase / short-wheelbase
- Bomb Service
- Chemical decontaminating
- Chemical handling
- Dental Operating Van
- Fire Engine
- Fuel tanker (750 US gal (2,800 l))
- High lift
- K-53 Van
- K-60 Van
- Ordnance Maintenance Van
- Pipeline equipment
- Pontoon bolster
- Surgical Van
- Water purification truck
- Water tanker (700 US gal (2,600 l))
The CCW[c] was an on-road 6x4 truck, the same as the CCKW except for the front wheel drive. A beam front axle was used, and the transfer case was locked in high range. Meant for on road use, it was rated at 5 tons.
The AFKWX[d] 353 also went into production in 1942 at Yellow’s Pontiac plant and Chevrolet’s in St. Louis. Mechanically the same as, and built next to, the CCKW, it had a cab over engine design, allowing a 15 ft (4.6 m), and later 17 ft (5.2 m) long cargo bed. The first 50 had closed cabs, the rest had open ones. Only cargo beds were used, and none had a front-mounted winch The COE design made it very hard to work on the engine. This was not a successful design, just 7235 were built.
The DUKW[e] “Duck” was an amphibious truck that shared the CCKW driveline. First built at Yellow’s Pontiac plant, demand increased and Chevrolet’s St. Louis plant also began building them. The hull, designed by an America's Cup winner, had excellent sea-keeping abilities. This was a very successful design, 21147 were built.
- The CCKW was known by its corporate name: C was date of design (1941), C was conventional cab, K (if used) was all wheel drive, and W was tandem rear axles.
- Measurements are from the centerline of the front axle to the centerline of rear bogie / rear axle.
- GM name: C for 1941, C for conventional cab, and W for tandem rear axles.
- GM name: A for 1939, F for forward cab, K for all wheel drive, and W for tandem rear axles.
- GM name: D for 1942, U for utility, K for all wheel drive, and W for tandem rear axles.
- List of U.S. military vehicles by supply catalog designation (G508)
- List of U.S. military vehicles by model number
- List of U.S. Signal Corps Vehicles
- General Motors
- M35 2½ ton cargo truck
- Chevrolet G506 trucks
- Studebaker US6
- David P. Colley (2000). The Road to Victory: The Untold Story of World War II's Red Ball Express. Potomac Books. ISBN 1-57488-173-6.
-  The Real History of World War II: A New Look at the Past by Alan Axelrod, Sterling Publishing Company, Inc., 2008, ISBN 1-4027-4090-5, ISBN 978-1-4027-4090-9
- "TM-9-2800 1943 Standard Military Motor Vehicles". http://www.scribd.com. US General Accounting Office. 1 September 1943. Retrieved 27 May 2014.
- "TM-9-2800-1947 Military Vehicles". http://www.scribd.com. US General Accounting Office. 27 October 1947. Retrieved 27 May 2014.
- Doyle, David (2003). Standard catalog of U.S. Military Vehicles. Kraus Publications. p. 108-118. ISBN 0-87349-508-X.
- Ware, Pat (2010). The World Encyclopedia of Military Vehicles. Lorenz Books. p. 238-239. ISBN 0-7548-2052-1.
- Crismon, Fred W (2001). US Military Wheeled Vehicles (3 ed.). Victory WWII Pub. p. 330-335. ISBN 0-970056-71-0.
- Crismon (2001), p. 184.
- Crismon (2001), pp. 326, 332.
- Crismon (2001), p. 465.
|Wikimedia Commons has media related to GMC CCKW.|
- TM 9-2800 Standard Military Motor Vehicles. dated 1 sept. 1943:http://www.scribd.com/doc/140198120/TM-9-2800-1943-STANDARD-MILITARY-MOTOR-VEHICLES-1-SEPTEMBER-1943?in_collection=4255113
- TM 9-2800-1 1953 INCL. C1 EN C2: http://www.scribd.com/doc/183017787/TM-9-2800-1-1953-INCLUDING-C1-EN-C2-pdf
- TM 9-2800 Military vehicles dated Oct. 1947: http://www.scribd.com/doc/188375301/TM-9-2800-1947
- TM 9-801: http://www.scribd.com/doc/155668936/TM-9-801-GMC-CCKW-352-353