Numbering Systems for US Military Vehicles

[muttguru]

An old friend of mine, Jim Allen, asked some questions on the G503 Board about a year ago. The questions concerned the system of hood numbering by the Military and the changes that were made over the years.
As no-one had responded to jim's questions, I thought it was time to put together a reply to explain it all. i did intend to copy it here (honestly I did) but like many good intentions, it fell by the wayside.
As lots of mutt owners have asked similar questions over the years, I thought it may be of interest when i was reminded about the posts recently.
So here it is:-

From Jim Allen. A few burning questions:-

1 Example: A 1970 Scout in service with the U.S. Army has the reg number 01M 28370. Going from back to front, I know the "70" is the year it went into service. I think I know the "283" is the number of the vehicle in the order (that correlates to what I see on Line Setting Tickets... the build sheets). I am confused on the "01M" as some earlier rigs are "1J" (1962) or "1N" (1965) and later, 1971, are "01C" and 1972 is "01B."

2 I have one Scout from 1970 that was part of a contract for the U.S. Army and even had a U.S. Army reg number when built, yet it never went to the Army and served with the USMC. It was reissued a USMC data plate. How does that happen?
Jim Allen ArmySailor G503

Reply from Ken (me):-

Jim, no-one else has answered so far so it looks like my turn. Here are some of the answers you’re looking for.

Your Question-1.
Leading up to 1960 the US Army numbering system was changed. Vehicles delivered from that point had a number (one digit) followed by a letter (the first one was A) and the four further digits beginning with 0001. When this number reached 9999, the letter changed to “B”. And the 0001 to 9999 sequence repeated. The letter “C” was next and you get the picture as to how the sequences moved forward.
But what about the one-digit number at the beginning of the sequence?....I hear you ask.
That number determined the vehicle type. For example, vehicle 2K 7183 was an M151A1, the number “2" designated the vehicle type (1/4-ton and 1/2-ton truck), the “K” was the next letter after A-through-J had been used up and the 7153 represented the number of 1/4 and 1/2-ton vehicles delivered in the “K”-series to that date. As you can probably gather, the M151 and M151A1-series vehicles formed the bulk of the “2" series vehicles but there were M274 mules with a “2" as well as a batch of M38A1s delivered around 1963 which were also numbered in the 2-series, such as 2G 0581 (dated around Sep-Oct 1964).
Your cars and sedans used by the US Army would begin with “1" most likely signifying civilian-type light vehicles adopted by the Military.

Your Question-2
The system of numbering vehicles lasted up to 1968 when the Army introduced a new numbering system. It went like this:-
The single digit now became a double-digit at the beginning of the registration (hood number).
The four-digit series was reduced to three with an addition of the last two digits of the year of delivery. For example, an M151A1 delivered in 1968 would have a registration number such as 02B 31768. As you can see, the first two digits defined the vehicle type, the 317 was the next vehicle in the 001 through to 999 sequence and the last two digits, 68, determined the year-of-delivery. This was a useful system of registration because not only troops, but us vehicle researchers, could identify the approximate year-of-delivery from the hood number.
The drawback was that unlike the registration format in Question-1 above, this new system only allowed for 999 vehicles to be included in the 02B-series before starting on the 02C-series. So the alphabetical series was used up in rapid time.
So how did the Military solve this problem? It simply added another letter to the “02", so the alphabetical series began again, this time with 02AA, then 02AB and so on. An example of this is M151A2 with registration number 02DE 8870. But... the addition of an extra digit meant the number of vehicles to be included in that batch was reduced to 99. Once 99 had been delivered, the next series would start again at 01 through to 99 but with a prefix of 02DF, then the system repeated for the next batch using 02DG and so on.
This system remained in place until 1973 when a further system (which is still in place) was introduced.

If you’ve followed all that.... good for you.
Ken

[Refit1701]

Good info. I like doing the detective work that some hobbies need. It's fun.