M35 2½-ton cargo truck

The M35 family of trucks is a long-lived vehicle initially deployed by the United States Army, and subsequently utilized by many nations around the world. A truck in the 2½ ton weight class, it was one of many vehicles in U.S. military service to have been referred to as the "deuce and a half." While the basic M35 cargo truck is rated to carry 5000 lb off road or 10000 lb on roads, they have been known to haul twice as much as rated. Trucks in this weight class are considered medium duty by the military and Department of Transportation. The M35 series formed the basis for a wide range of specialized vehicles.

Design and development
The M35 started out in 1949 as a design by the REO Motor Car Company as a 2 1/2 ton three axle all wheel drive off road truck that was later nicknamed the "deuce and a half". The first vehicle in the family, the M34, was quickly superseded in military usage by the M35, the major difference being the M35's 10-tire configuration versus the M34's 6-tire configuration.

An M35A2 cargo truck with winch is 112 in tall, 96 in wide and 277 in long, and 15030 lb empty   (15530 lb empty when equipped with the front mount winch, according to dashboard dataplates). The standard wheelbase cargo bed is 8 feet by 12 feet (2.4 x 3.6 m). The M35A2 was available with a canvas soft top, as pictured, or a metal hard top. Metal hard-top configurations are most often found on vehicles that have been equipped with cold-weather gear, including additional insulation in the cab, as well as engine coolant or multifuel-fired cab personnel heaters.

The M35A2 is popularly powered by an LDT 465 engine, made by either Continental Motors Company, Hercules, or White Motor Company. It is an in-line, 478-cubic-inch (7.8 L), six-cylinder, turbocharged multifuel engine developing 134 bhp and 330 lbfft of torque. This is coupled with a 5-speed manual transmission and divorced 2-speed transfer case (either a sprag-operated transfer case Rockwell 136-21 or air-operated selectable transfer case Rockwell 136-27). Multifuel engines are designed to operate reliably on a wide variety of fuels, to include diesel fuel, jet fuel, kerosene, heating oil or gasoline. Gasoline should only be used in an emergency because it does not properly lubricate the injector pump. While using gasoline, common practice calls for the addition of at least 1 U.S. quart of clean motor oil per 15 U.S. gallons of gasoline (1 imp qt/13 imp gal; 1 L/60 L) for proper pump lubrication where available.

Although the A2 version is by far the most common, there are four different iterations: Standard, A1, A2, and A3 iterations. These changes mainly had to do with the engine and transmission components. Standard M35 had a REO "Gold Comet" or Continental OA331 inline-6 gasoline engine. Some had 4-speed transmissions but most had "direct 5th" transmissions. The gasoline-powered deuces were built primarily by REO Motors, however, Studebaker also had a manufacturing contract from at least 1951 up into the early 1960s. Curtis-Wright also had a contract in at least 1958 to build dump trucks with the Continental gas engine. The A1's had Continental LDS-427-2 turbo engines,equipped with either a model 4-450 Schwitzer turbo, or a 4D454C Schwitzer turbo on later models, and 5th gear was an overdrive. The 140 hp engines were not reliable, suffering frequent headgasket failures. First A2 trucks received the bigger LD-465-1 naturally aspirated 478 CID Multifuel engines, keeping the OD transmission of the A1s. Through the years the trucks were upgraded to LD 465-1c engines, with 60Amp alternator instead of the 25Amp generator. With the addition of a turbo, this engine evolved into the LDT 465-1c (turbo clean air). The turbo was added more to clean up the very black exhaust on the Non Turbo engines, than to add power, the HP was only raised from 130 to 135 HP.Turbo models used: 3LD305(early engines only) and 3LJ319 (the "whistler") The LDT-465-1D was the last version of the Multi Fuel, it had the same 3LJ319 Turbo(whistler), or the quieter 3LM39 (non-whistler), better head gasket sealing and head cooling.

In 1994 the M35A3 variant was introduced as part of Extended Service Program, and between then and 1999. Usually, A3 vehicles have a Caterpillar 3116 Diesel engine and had their manual transmissions replaced with automatic ones, as well as receiving numerous other improvements and a redesigned frontal appearance. No new A3 standard-transmission vehicles were produced, all vehicles being upgraded from previous configurations.trucks during the rebuild process. The exception to the rule are some M109A3 shop vans, a small number of M109A3s were upgraded to A4 specs using the M35A3 upgrade parts and procedures. As-built original A1's are gassers, A2's are LDS 427-2 multifuelers,and A3 are LD/LDT 465-1c multifuelers. however it is still common to find rebuilds of former gas-powered REO and Studebaker models having A1 and A2 multifuel configurations.

The curb weight of an M35 is between 13000 lb and 16000 lb empty, depending on configuration (cargo, wrecker, tractor, etc.). Its top speed is 56 mph, though maximum cruising speed is approximately 48 mph. Fuel economy is 11 mpgus highway and 8 mpgus city, giving the deuce a 400-500-mile (600–800 km) range on its 50 u.s.gal single fuel tank. On average, most operators experience tank averages of 8 - 10 mpgus for an unladen vehicle.

Brake system is air-assisted-hydraulic six wheel drum with a driveline parking brake, although gladhands exist on the rear of the vehicle for connection to trailers with full air service and emergency brakes. Braking performance of the truck is similar to other power drum brake vehicles of this size. Each drum was designed with maximum efficiency in mind, and individual drums can dissipate up to 12 kW of braking heat. Due to this brake system and GVWR under 26001 lb, the big deuce can be driven without a commercial driver's license in most states. Even California does NOT require a CDL to operate an M35 on public roads because even though it has three axles and an air-assisted braking system, the maximum gross weight is still under 26000 lb, making it eligible for class C on-road driving; and because the primary braking system is hydraulic, not air.

The electrical system is 24 volt, using two 12 volt 6TL-series military grade batteries run in series.

Some deuces are equipped with a 10000 lb PTO-driven front winch manufactured by Garwood.

Operational history
The M35 family was introduced into the U.S. military to replace the GMC CCKW and M135 families cargo trucks still in service at the time. The M35 would not completely replace the M135 family until the middle of the 1960s. However, the M35 would quickly become the dominant truck in its class in the U.S. military, serving with all the services in various capacities. For a short period the M35 was called "The Eager Beaver" by the U.S. Army due to its fording ability. But the name was never popular and forgotten in a few years.

The M35 series was to be replaced by the Light Medium Tactical Vehicle. However, many United States National Guard and Reserve units continued to use them as the new family of vehicles was phased in. The M35 series was used by the United States in Iraq during Operation Iraqi Freedom. The M35 Truck was not used by the United States Marine Corps and currently issued M35 to the U.S. Army Service.

The Canadian Army adopted license built versions of the M35 (and M36 variant) in 1982, built in Canada by Bombardier. As of 2008, the trucks, designated MLVW (Medium Logistics Vehicle, Wheeled) were still in service. Canadian vehicles featured an automatic transmission, six wheels instead of ten (using single wheels on the tandem rear axles instead of dual wheels), and an ether-start for winter operations. Canada had been investigating a replacement under the Medium Support Vehicle System Project, and a vehicle has been selected. The MLVW's were initially not deployed with Canadian Forces in Afghanistan because of their lack of armor protection. An armor kit was subsequently developed leading to a limited deployment of the vehicles.

Variants
The M34/M35 series of trucks came in wide array of variants and subvariants. As noted engine differences could be noted by the A1, A2, or A3 suffix, but additional suffix letters were also sometimes added. These letters had different meanings depending on what variant to which they were applied.

Under the nomenclature system used by the U.S. Army Ordnance Corps Supply Catalog (known as G-series) the M34/M35/M36 family is designated G742.

Cargo variants
As noted the original basic gasoline-powered truck variants were first the M34, and then the M35. A long wheel-base variant, designated the M36, was also developed (featuring a 16 ft cargo bed). Variants with a C suffix (such as M35A2C or M36A2C) featured a straight drop-side cargo bed. The M44 and M45 were simply the chassis designation for the 2½ ton series, and this cab/chassis would serve as the basis for many more specialized variants.

In the 1980s, Bombardier produced a M35 variant for the Canadian Forces' medium logistic vehicle, wheeled platform. This featured an Allison MT-643 automatic transmission, and a Detroit Diesel engine displacing 500 cubic inches (8.2 L). The original 11.00X20 Bias ply tires on split ring type rims were later changed fleet-wide to Michelin radials on bolt-together rims in 2002, due to safety concerns over the split rims.

Tank truck variants
The M49 fuel tanker and M50 water tanker variants were initially based on the M44 chassis. The M49C series, however, were vehicles converted from C series drop-side cargo variants. M49's have 1200-gallon tanks. Early models had triple compartments (200g front, 400g mid, baffled 600g rear),but most models have two 600-gallon baffled tanks. The M50 had a 1000 u.s.gal water tank, of which later variants had internal baffles to combat weight transfer during motion. In some areas the M35 is still used today as a wildland firefighting truck with a portable water supply and fully operational pump.

Van variants
A number of variants with van bodies, primarily for use as maintenance shop vans, were also created. The basic model was the M109, with a variant that could not mount the PTO winch was designated M185. An expandable van variant with hydraulic lift gate was designated M292. Two variants of the M109 were specifically developed as service vehicles for the MGM-18 Lacrosse missile system, the XM411 for the Ground Guidance Electronic Equipment, and the XM412 with special tools and test equipment for the electronic guidance and control system. A medical van variant was designated M132.

Wrecker and Tractor variants
A wrecker based on the M35 truck was designated the M60. Two tractor variants for towing semi-trailers were developed, the M48 and M275. The M48 featured a full-length wheelbase (identical to the M35 cargo), while the M275 featured a shorter wheelbase for reduced weight and greater maneuverability. However, due to the smaller size and lower power of the 2½ ton trucks, most heavier loads were handled by their respective 5-ton counterparts. As a result few were produced.

Construction variants
A number of specialized construction variants were developed. The M47 and M59 dump trucks were developed, based on the M44 chassis and M35 cargo truck respectively. An improved dump truck, again based on the M44 and designated the M342 was designed to replace both the M47 and the M59, as well as the M135-based M215.
 * Also under the M44 chassis was the signal corps V-17 pole derrick, and the V-18 auger truck, later replaced by the M35 upgrade below.

The M108, based on the M44 chassis, carried a crane and was used for many tasks including to deploy missiles such as Lacrosse. The M756 was a specialized pipeline repair vehicle, the M763 was designed for telephone line repair, and the M764 was a specialized earth-boring and pole-setting variant.

Gun trucks
The versatility of the pattern was perhaps shown best in its usage as an armored "gun truck" for patrol duties and convoy escort.

The simplest examples were produced by simply placing an existing light gun mount directly onto the cargo bed of the truck, and securing it in place. No armouring or special support equipment was installed. One such conversion was performed in Congo-Leopoldville in 1965, using an Oerlikon GAI 20 mm anti-aircraft gun. Another conversion in the Congo entailed mounting pods with 2.75" aircraft rockets on a pedestal on the cargo bed, but this proved unsuccessful.

The first more sophisticated conversions of the pattern were performed by the U.S. military in Vietnam. U.S. Army Artillery Battalions (Automatic Weapons, Self-Propelled) were often assigned Artillery Batteries (.50-caliber), units equipped with M35 trucks and M55 Quadmount systems mounting four M2 Browning machine guns. Units were also authorized a single M60 machine gun and M79 grenade launcher. While the M35 was designed to act as the prime mover for the M55 Quadmount system, which included a towed trailer, the M45 mount was often removed or the wheels removed from the trailer, and the system mounted on the bed of the truck. The M55 system was also mounted on the M54 truck.

More simplified armoring projects were conducted as well, adding armored walls of various thicknesses to standard cargo variants. A smaller bed-mounted multi-angle "box" was also tried. U.S. Army gun trucks used a wide variety of weapons including the M2 Browning machine gun, M60 machine gun, and even the M134 Minigun.

At the end of the Vietnam War most of these vehicles were returned to their standard configuration, except for a single original example shipped to the U.S. Army Transportation Museum at Fort Eustis, Virginia in 1971.

Numerous Vietnam veterans have expended countless hours to build full size replicas of their original Gun Trucks, using M35, M54, and even Army Dump Trucks as platforms, much the same as these veterans did in Vietnam. A functional display replica of the "Psychotic Reaction" Gun Truck Based on an M35A2 chassis is currently in use and being displayed at many military vehicle displays and Vietnam veteran reunions / events.

The concept lived on well after the Vietnam War. El Salvador converted a number of M35 type vehicles into armored trucks in the 1980s, after successful conversions of Magirus Deutz trucks. These vehicles were nicknamed "Mazingers" in reference to the Japanese cartoon Mazinger Z.

The Philippine Marine Corps also began converting M35 type trucks to an armored configuration by 2004. The first vehicle, dubbed "Talisman," utilized armor fabricated from derelict LVTP5 amphibious personnel carriers. Later gun trucks were built using more standard components and bear some resemblance to U.S. military vehicles of the Vietnam era. The Philippine Marine Corps had also begun the creation of an anti-aircraft element by 2006, utilizing M35 based vehicles. Two types of vehicles have been seen so far. One utilizes the Mk 56 Mod 0 mount from the Patrol Boat, River, with two M2 Browning machine guns, while the other features another former naval mount with a single Oerlikon 20 mm cannon.

Colombia maintains a fleet of REO M35 "Meteoro" armored trucks. These locally fabricated armored vehicles are used to guard tourist bus caravans as well as mobile checkpoints. Early vehicles were not fabricated to any particular standard and typically hosted three weapon stations that could be fitted with a 7.62 mm (.308-cal) or .50-caliber (12.7 mm) machine gun. The weapon stations may or may not have had a gun shield on any particular vehicle. More recent examples follow a pattern with the cab and fuel tanks armored and the drop side cargo bed converted to an armored box, atop which is a "gun tower," a set of four heavily armored weapon stations, one facing each direction. .50-caliber machine guns are mounted front and back, with 7.62 mm machine guns mounted to the sides. Losses in the Meteoro fleet instigated the purchase of the BTR-80 Caribe.

Civilian conversions
The M35-series trucks have been sold as surplus both to military vehicle collectors and to persons or organizations looking for an inexpensive truck capable of off-road operation. Users have included farmers, rural electric utilities and fire departments. Surplus vehicles may be retained in military configuration, or modified to suit the needs of their new owners. Such modifications may include "bobbed" chassis with one of the rear axles removed, new cargo beds or boxes, fuel or water tanks, and conversion of the electrical system to 12 volts.

Operators

 * 🇦🇷 Argentina
 * 🇦🇹 Austria
 * 🇧🇷 Brazil
 * 🇨🇦 - Canadian Forces/Canadian Army
 * Democratic Republic of Congo
 * 🇩🇴 Dominican Republic
 * 🇪🇬 Egypt
 * 🇭🇳 Honduras
 * Republic of Macedonia
 * 🇲🇽 Mexico
 * 🇲🇨 Monaco
 * 🇳🇮 Nicaragua
 * 🇸🇪 Sweden (evaluation only)
 * 🇭🇳 Honduras
 * Republic of Macedonia
 * 🇲🇽 Mexico
 * 🇲🇨 Monaco
 * 🇳🇮 Nicaragua
 * 🇸🇪 Sweden (evaluation only)
 * Republic of Macedonia
 * 🇲🇽 Mexico
 * 🇲🇨 Monaco
 * 🇳🇮 Nicaragua
 * 🇸🇪 Sweden (evaluation only)
 * 🇸🇪 Sweden (evaluation only)
 * 🇸🇪 Sweden (evaluation only)
 * 🇸🇪 Sweden (evaluation only)
 * 🇸🇪 Sweden (evaluation only)