The M35 2½-ton cargo truck is a long-lived 2½-ton 6×6 cargo truck initially used by the United States Army and subsequently utilized by many nations around the world. Over time it evolved into a family of specialized vehicles. It inherited the nickname "Deuce and a Half" from an older 2½-ton truck, the World War II GMC CCKW.

The M35 started as a 1949 M34 REO Motor Car Company design for a 2½-ton 6×6 off-road truck. This original 6-wheel M34 version with a single wheel tandem was quickly superseded by the 10-wheel M35 design with a dual tandem. The basic M35 cargo truck is rated to carry off-road or on roads. Trucks in this weight class are considered medium duty by the military and the Department of Transportation.

Specifications

Dimensions An M35A2 cargo truck with a PTO-driven Garwood front winch is tall, wide and long, and empty ( empty when equipped with the front mount winch, according to dashboard dataplates). The standard wheelbase cargo bed is 8 feet wide by 12 feet long (2.4 × 3.6 m), with only 7.25 feet of this width being flat floorspace between the stake-pockets, the tailgate rising 16 inches above the floor and the side-walls/stake-pockets rising 12 inches above the floor. The M35A2 was available with a canvas soft top 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 curb weight of an M35 is between and empty, depending on configuration (cargo, wrecker, tractor, etc.). Its top speed is , though maximum cruising speed is approximately . Fuel economy is highway and city, giving the vehicle a 400–500-mile (600–800 km) range on its single fuel tank. Most operators experience an average of for an unladen vehicle.

The 6-wheel M34 had a single-wheel tandem and used 11:00×20 size tires, which required a wheel well in the cargo bed, while the 10-wheel M35 had a dual-wheel tandem and used smaller 9:00×20 tires, which did not require a wheel well.

Drivetrain The M35A2 is commonly 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 and of torque. This is coupled with a 5-speed manual transmission and divorced 2-speed transfer case( note -hidden gear in low range, shift up to 4th in high range, shift transfer to low, trans to 5th then transfer to high 5th again).(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, including diesel fuel, kerosene, heating oil or gasoline. Gasoline may be used only 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 the most common, there are four different iterations: Standard, A1, A2, and A3. 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 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.

The 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 turbocharger, the engine evolved into the LDT 465-1c (turbo clean air). The turbo was added more to clean up the black exhaust on the Non Turbo engines, than to add power; the HP was raised from 130 to only 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.

M35A3 From 1994 until 2006, the M35A3 variant was introduced as part of Extended Service Program. Usually, A3 vehicles have a Caterpillar 3116 Diesel engine and had their manual transmissions replaced with Allison 1545 4-speed automatic transmissions, as well as receiving numerous other improvements with a redesigned frontal appearance. No new A3 manual transmission vehicles were produced, all vehicles being upgraded from previous configurations during the rebuild process. The exception is some M109A3 shop vans. A small number of M109A3s were upgraded to A4 specifications using the M35A3 upgrade parts and procedures. As-built original Pre A2s are gasoline-powered, A1s use the LDS 427-2 multifuel engine, A2s use the LD/LDT 465-1c multifuel engine, and A3s use the Caterpillar diesel. It is common, however, to find rebuilds of former gas-powered REO and Studebaker models having A1 and A2 multifuel configurations. The original contract for the M35 - Service Life Extension Program was competitive. The last two companies to send vehicles to Aberdeen Proving Ground were AM General, South Bend, IN and Cummins Military Systems, Augusta, GA (AMG was awarded third quarter of 1993).

Brakes The brake system is air-assisted-hydraulic six-wheel drum brakes 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 of braking heat. Due to this brake system and GVWR under , the M35 can be driven without a commercial driver's license in most states.

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

Operational history

The M series truck family was introduced in 1949 to replace the GMC CCKW and M135 family cargo trucks that constituted the backbone of U.S. military transport since their introduction in World War II. 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 M34 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 Submarine Truck's Secrets", June 1951, Popular Science scroll page past diver to see trucks

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. M35 series vehicles were known to be in use by National Guard units as late as the mid-2000s.

In order to replace its 1950s vintage M135 fleet, the Canadian Army adopted licensed versions of the M35 (and M36 variant) built in Canada by Bombardier in 1982. As of 2020, the trucks, designated MLVW (Medium Logistics Vehicle, Wheeled) were still in service although limited spare part supplies forced the fleet managers to cannibalize from selected donors. Canadian vehicles feature a hard cab roof, an adjustable driver's seat, an Allison MT-643 automatic transmission, a Detroit Diesel engine displacing 500 cubic inches (8.2 L), six wheels instead of ten (using single wheels on the tandem rear axles instead of dual wheels), and an ether-start for winter operations. The original 11.00X20 bias ply tires on split ring wheels were later changed fleet-wide to Michelin radials on bolt-together wheels in 2002 due to safety concerns. Canada had been investigating a replacement under the Medium Support Vehicle System Project, and a vehicle has been selected. The MLVWs 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.Priestly, Stephen. Canadian American Strategic Review. June 2006. "Of Muddles and Medium Trucks – MLVWs and the Perils of Being Out-of-Step". Access Date: 26 April 2008.

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 United States Army Ordnance Corps Supply Catalog (known as G-series) the M34/M35/M36 family is designated G742.

Cargo

As noted the original basic gasoline-powered truck variants were first the M34, and then the M35. An extra long wheel-base variant, designated the M36, was also developed (featuring a cargo bed). Variants with a C suffix (such as M35A2C or M36A2C) featured a straight drop-side cargo bed. M44, M45, and M46 simply designated the long single tandem, long double tandem, and extra long double tandem chassis for the M35 -ton series of trucks; there was also a short tandem chassis without an M designation. These cab/chassis would serve as the basis for many more specialized variants.

In 1982, 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 wheels were later changed fleet-wide to Michelin radials on bolt-together wheels in 2002 due to safety concerns.

Tank truck

The M49 fuel tanker and M50 water tanker variants were initially based on the M45 chassis. The M49C series, however, were vehicles converted from C series drop-side cargo variants. M49s have 1,200-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 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