Dating a Deuce: G-742 2-1/2-ton Cargo Truck Production

by David Doyle, copyright 2017

Troopers wait as 2 1/2 ton cargo trucks are loaded somewhere in Korea, June 1970. The vehicles are a mixture of horizontally and vertically exhausted naturally aspirated Multifuel trucks. In the foreground, a M35A2 that was scarcely a year old when this photo was taken. How do we know? – read on! National Archives and Records Administration photo

The G-742-series cargo trucks—typified by the M35A2—have become an iconic symbol of U.S. military transport, having been the backbone of this service for half of the last century.

Whereas production of the WWII Jeep, and even the various Dodge tactical trucks are well-documented, the history of the M35A2 has remained shrouded in mystery. Mistakes on the part of government employees, as well as civilian contractors, have further fogged the history of these trucks.

In this article, we will unravel some—but not all—of the mystery surrounding this vehicle. This information was derived from the examination of more than 1,000 vehicles.

The Basics

The G-742 series trucks were produced by a number of companies—Reo, Studebaker, Lansing Division of White, Curtiss-Wright, Utica-Bend, Studebaker-Packard, Kaiser-Jeep, General Products Division, and AM General.

Despite the wide range of manufacturer’s names, in reality the trucks can be broken down into two groups: Lansing-built trucks and South Bend-built trucks.

When the G-742 series trucks, typified by the M35, entered production, the US Army used an eight-digit registration number system. Though critical to the army for record-keeping purposes, the registration number itself provided little useful information to the casual observer. However, examination of hundreds of trucks seems to point to registration numbers beginning with 412, like this truck at Kaiserslautern, Germany, were built by Reo, while those registration numbers beginning 411 were built by Studebaker. National Archives and Records Administration photo

The first step in this process is understanding what is meant by the terms serial number, registration number, and VIN.

The serial number is the number assigned by the vehicle manufacturer, and it is embossed in the frame. This number is of great interest to the truck builder, and to a limited number of parts men within the military, but of no interest to the military for record-keeping purposes.

The registration number, sometimes referred to as the “hood” or “USA” number, is assigned by the military and is the number used by the military for records-keeping purposes. It is roughly equivalent to the license plate number of your car.

When a contract (order) for trucks is placed with a builder, the contract specifies the range of registration numbers to be applied to those vehicles. The contract does not require that they be applied in the same sequence as the manufacturer’s serial number, though in some cases it is. With almost no exceptions (primarily armored vehicles), the registration number of a vehicle— once assigned—does not change during the life of the vehicle.

The true manufacturer’s serial number of Kaiser-Jeep, General Products, and AM General 2 1/2 ton cargo trucks was stamped by the truck builder into the left side frame rail near the front axle. These numbers, as shown here, include a four-digit prefix and a five-digit suffix.

The manufacturer’s serial number: Today many organizations such as auto parts stores, insurance companies, and including most state motor vehicle agencies reference a Vehicle Identification Number (VIN).

VINs were first introduced in 1954—and in 1981 the National Highway Traffic Safety Administration, through the Code of Federal Regulations part 565, standardized the format of the VIN to be 17 characters, and specified that they were not to include the letters I, O, or Q.  These rules impacted vehicles built or imported for sale and on-road use in the US.

The number embossed in the frame should match the number on the dashboard-mounted data plate. The “MFR. No.” stamped in this Kaiser-Jeep built truck’s data plate, 0225-21735, not only exactly matches the frame number shown in the photo to the left. The plate also handily includes the year manufactured – 1967.

This is significant in that military G-742 trucks were built for the use of the Federal Government, rather than sale through a dealer network.  Hence, these trucks do not have VIN numbers, much-less 17-digit VIN numbers.  While this may be confusing to younger staffers at the local DMV, because NO older vehicles had VINs, this is not a completely foreign concept.

What these trucks have (as well as what a 1952 Chevy Bel-Air has) is a “manufacturer’s serial number.”

Lansing-built trucks

Trucks built in Lansing, Michigan, carry data plates reading Reo Motors, Reo Division of White, Lansing Division of White.  These trucks have six-digit all-numeric manufacturer’s serial numbers, which in addition to appearing on the cab data plate, are also embossed in the truck frame rail under the front fender.

South Bend-built trucks

Initial production of the G-742 trucks in South Bend, Indiana, was undertaken by Studebaker in the 1950s.  These trucks also have six-character manufacturer’s serial numbers, but the first character is the letter “M”—followed by five numbers.

This was the pattern used on the South Bend-built trucks up until Kaiser-Jeep bought the Studebaker Chippewa Avenue truck plant (formerly an aircraft engine plant) in February 1964.

Kaiser-Jeep introduced a new type of manufacturer serial number numbers, a system that would encode some of the characteristics of the vehicle, and would remain in place, with a few changes, until the end of G-742 production.

The Kaiser-Jeep manufacturer’s serial number is stamped on the frame of the truck, near the steering box under the left front fender. It is a nine-digit number divided into a four-digit prefix and a five-digit suffix: “0525-23669,” for example.

My analysis of the production of these vehicles further breaks this number down. Please note that the terms I use here describing them are of my own choosing, and not from official sources.

The first two digits I will refer to as “lot number.” The second number is a chassis designator. The final five are the sequence number.

The first two digits, or lot numbers, range from 1 through 10. However, I have yet to find, or hear of, a truck with an 07 prefix. My suspicion is that these vehicles were produced by AM General for sales to a foreign government. Any confirmation—or contradiction—of this, will be appreciated.

The next two numbers, or chassis designator—indicates the type of truck along these lines:

21- M44A2 cab and chassis

22- M46A2C

23- M342A2

24- M275A2 without winch

25- M35A2 without winch

27- M36A2 extra long wheel base cargo without winch

28- M49A2C

30- M185A3 without winch

32- M109A3

33- M292-style expansible van

34- M45A2 without winch

35- M756A2

36- M764

39- M35A2 with winch

40 – M35A2C dropside

41- M35A2C with winch, dropside

44- M45A2 with winch

46- M36A2 with winch

47- M50A3 without winch

There are some exceptions to this. For example, the earliest M35A2C dropside cargo trucks were built on chassis with 25 designators and the 40 designator does not appear until the fifth lot.

Notice that there are some numbers “missing” from the above list—specifically 26, 29, 31, 37, 38, 42, 43 and 45. Any reader with evidence of what type of trucks used these chassis are asked to contact the author.

The final five-number sequence number begins at approximately 10000, and begins anew at that number each time the lot number changes. However, evidence thus far indicates that each five-digit suffix is unique within that lot. That is to say, there are not both a “0525-10011” and “0527-10011.” I believe it is safe to say that within lots the sequence numbers were just that—assigned chronologically, in sequence.

With this, knowing production dates of some of these vehicles will allow us to determine the dates of others. In some instances, the production dates are handily embossed on the frame, or even on the dash-mounted data plates. In other cases, we must be a bit more resourceful. One place we can turn to for assistance is the registration number.

The Registration Number

The registration number, used in conjunction with the VIN, can be used as a guide to a vehicle’s history. Through the years, the Army has used various sequences of characters for the registration numbers. Some of these can be very useful when dating a cargo truck.

1951 through 1960

During the earliest G-742 production, the army registration number system was essentially the same as it had been during WWII. The M34, M35, and M36 cargo trucks were assigned eight-digit registration numbers, the first digit of which was four, which denoted 2-1/2-ton truck.

1960 through 1968

From 1960, a new system was introduced, comprised of numbers and a letter, such as 4B 1234. The initial “4” signified 2-1/2-ton truck. When the registration number reached 4B 9999, the next letter was used, as in 4C 0001, etc. Some letters were NOT used because they could be confused with numbers (such as I and O).

1968 through 1972

In 1968, this system was replaced with what, at least from the collector’s standpoint, was the ideal registration number system. This system incorporated a “Year” as the last two digits of the registration number. 04A-46468 is an example of such a registration number. In the case of our example, we know from the 04 prefix it is a 2-1/2-ton truck, and from the final two digits that it was a 1968 model.

1972 through 1982

Collectors bliss was short-lived however, as by the end of 1972, the system changed once again, and the “NK” numbering system was introduced. This is system is a little more vehicle- specific than the previous systems, in that the alpha prefixes denotes vehicle families rather than just weight class.

While NK was used to designate Multifuel 2-1/2-ton cargo trucks, NH and NJ were also used,  designating diesel- and gasoline-powered vehicles, respectively. The year of delivery was no longer incorporated into the registration number.

1982 through 1987

The final G-742 trucks were not built for the army, but for the US Air Force. The USAF  had its own system of assigning registration numbers.  Like the Army system introduced in 1972, this system included a year designator, but at the front of the registration number rather than at the rear. An example of this is 87K2371. The “newest” of these trucks that I have been able to document was a 1989 model.

In later years, the data plate included an “identification number” which was an amalgamation of both the manufacturer’s serial number, and the army registration number. In this example, NK078Z is the registration number, while 0640-11347 is the true manufacturer’s serial number of the vehicle.

What about the contract number?

Starting in about 1968, the Army acquisition contract number appears on vehicle data plates. Buried with in this lengthy number is the contract year. For example, contract DAAE06-70-C-0001 was issued in 1970. However, vehicles often were still being delivered under a given contract number even many years later. Therefore, the contract date should not be confused with the production date of a vehicle.

Who built my truck?

As stated in the introduction, this article concerns only three of the many makers of the M35-type trucks. A little history is perhaps useful in understanding the many nameplates found on these vehicles.

Reo Motors of Lansing Michigan developed this family of vehicles in 1949 and began producing them shortly thereafter. Copies of the Reo-designed vehicles were ordered from South Bend, Indiana-based Studebaker Corporation in the early 1950s. This move was spurred, in part, by the national defense crisis of the Korean War (when there were real concerns that it would evolve into World War Three), as well as the desire—both from a strategic and political standpoint—to bolster the sagging sales of Studebaker.

In March 1963, the name of Willys Motors, Inc. was changed to Kaiser-Jeep Corporation. One year later, in March 1964, Kaiser-Jeep took over Studebaker’s military contract for 5-ton trucks and purchased Studebaker’s Chippewa Avenue plant in which to produce them.

In February 1970, American Motors Corporation purchased Kaiser-Jeep. On March 26, 1970 Kaiser-Jeep became the Jeep Corporation.

The South Bend facilities were part of the General Products Division. Just over a year later, on March 31, 1971, The General Products Division of the Jeep Corporation was spun off and became AM General, a wholly owned subsidiary of American Motors.

In 1983, cash-strapped American Motors sold AM General to LTV Corporation. Nine years later, a bankrupt LTV Corporation sold AM General to a group of private investors known as the Renco Group for $133 million.

The early production multifuel cargo trucks bore registration numbers of the style used on this 1967 Kaiser-Jeep M35A2 exiting LST664 at Saigon in July 1968. The first digit “4” identifies this truck as a 2 1/2 cargo truck. This system was in use from 1960 until 1968. National Archives and Records Administration

Lot Numbers

In the absence of knowing the terminology used by the manufacturer’s, I have chosen to use the term “lot number” to describe the first two digits of the manufacturer’s serial number.

The “01” lot designator was used throughout 1966, and into the early part of 1967. These trucks were built by Kaiser-Jeep, as were lots 02 and 03.

The “02” lot designator appeared early in 1967—sequence number 18273 is the lowest (thus far located) 1967 manufacturer’s serial number, and it was assigned registration number 4L-7291. Sequence number 23138 was built February 7, 1968, and assigned registration number 4M-2102. The highest sequence number located in lot 02 is 28762.

Designator “03” appeared in 1968, as denoted by the registration number (04A46468) of the earliest known “03” truck—sequence number 10011. By sequence number 10703, the New Year had rung in, and the registration numbers had reached 04E11869. This truck was likely produced at the very end of the year, as a handful of trucks with lower sequence numbers were assigned 1968 registration numbers. Remember, at this point in time, the registration numbers were applied to the trucks after they were built and inspected—not as they rolled off the assembly line.

The “highest” production number 1969 truck I have located is serial 25519, which was assigned registration number 04M-97669. The earliest 1970 truck located thus far is 26386, which was given registration number 04A36970. The newest “03” lot truck I have found is 30254, which was assigned registration number 04D59970. Lots 01, 02, and 03 all have Kaiser-Jeep data plates.

Except for the seemingly absent lot “07” vehicles, lot “04” appears to comprise the smallest group of Kaiser-Jeep-built vehicles, with only a 3500 number documented span of sequence numbers. The registration numbers used are predominately 1969 series numbers. These truck likely represented a new contract, rather than the more typical addition to an already existent order.

In contrast, one of the largest groups of these vehicles was contracted in 1970: Lot “05” included some 16000 trucks. Production of this lot spanned three manufacturers. The first of these appeared with Kaiser-Jeep data plates, followed by the brief use of General Products Division plates, and finally AM General nameplates.

Registration number 04E56470 is the earliest known truck of this group, this 1970 Kaiser-Jeep truck was assigned sequence number 10020. By 1971, when sequence number 10290 was used General Products Division was the name appearing on the data plates. That truck was given registration number 04C10871.

AM General was the badge applied to sequence number 10548, another 1971 product. The registration number of this vehicle was 04D66971. As production of the lot “05” vehicles reached sequence number 25966 in 1972, registration numbers rose to NK01LC72.

Dropside cargo trucks apparently began to get their own chassis designator digits in 1972, as none have surfaced with the pre-1972 style registration number. Prior to 1972, the dropside cargo trucks used the same chassis designator as the conventional cargo trucks.

Lot “06” vehicles were contracted in 1973, and naturally all of the vehicles in this (and subsequent lots) were built by AM General. Details of year model breaks have eluded me thus far, but at least 2,000 vehicles were produced on the contract.

As mentioned earlier, no lot “”07” vehicles have yet surfaced. This leads us to lot “08,” a small lot of about 500 trucks. Trucks from sequence number 10000 through about 10400 were produced in 1982 production. A few trucks exist with sequence numbers in this range and 1983 registration numbers—this is likely indicative that production of this lot began late in the year. Only a few trucks are sequentially numbered as 1983 production. The registration numbers for these trucks were assigned in the same sequence as the serial number—for example, when the serial number increases by two, so does the registration number.

Lot “09” vehicles apparently were almost all produced in 1985, with only a handful of the 1,000 or so vehicles of this lot leaving the assembly line in 1986.

Lot “10,” the final lot, left the Chippewa Avenue plant in 1987. The registration numbers for these trucks began with “87,” and like the lot 8 and 9 vehicles, were assigned in the same sequence as the manufacturer’s serial number.

From 1968 into 1972 the last vehicle’s year model was incorporated as the last two digits of the registration number. In the case of this new 1970 naturally aspirated M35A2 being tested at Aberdeen Proving Ground. Fred Crismon collection

Powerplant

From the inception of the G-742 (M35-type) trucks in 1949 until 1960, the vehicles were powered by the Reo-designed OA-331 six-cylinder gasoline engine. In 1961, the six-cylinder LDS-427-2 Multifuel engine replaced it in most of these chassis types, including the cargo trucks. This turbo-supercharged engine was not equipped with a fuel density compensator, a hallmark of later Multifuel powerplant.

The exhaust routing was similar to that of the gasoline-powered trucks: Horizontal and exiting above the tandems on the right side of the vehicle.

Beginning in June 1965, the the naturally aspirated LD-465-1 Multifuel engine replaced the LDS-427-2. The new engine featured a horizontal, muffled exhaust.

With the introduction of the LD-465-1C, the exhaust routing was changed from horizontal to vertical. For environmental reasons, the LD-465-1C, in turn, was replaced by the turbo-supercharged LDT-465-1C. As the earlier engines wore out, they were to be replaced with the LDT. The LDT-465-1C was eventually replaced by the LDT-465-1D.

The previously mentioned exemption requested from the EPA was to allow the purchase of 15,000 2-1/2 ton truck engines over 5-year period. Instead of the desired five-year waiver, on September 30, 1987 the EPA granted a one-year exemption for only 3,000 engines—at the time directing the Army to “… establish a program to develop a cleaner configuration for the current engine.” This move—likely more than anything else—sealed the fate of the longest-serving tactical vehicle design in the army’s history.

Taken by AM General, this 1975 photo of a new M35A2C illustrates the registration number system employed from 1972 through 1982. Note when the military moved away from the overall semigloss olive drab paint scheme, the large white registration markings were abandoned as well. In their stead were smaller markings in black on the underside of the hood and inside the doors. U.S. Army TACOM LCMC History Office

Your help is needed

Research is ongoing toward writing a history of these remarkable, long-serving vehicles. The final product will be comparable to my earlier books on Dodge military vehicles and my 504-page book on the GMC CCKW.  If you were involved with any of the manufacturers of these trucks or their bodies, please contact the author via email at David@DavidDoyleBooks.com.

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