Truck 2-1/2 Ton 6x6 GMC ST-6 Bodies (And ST-5 Bodies)

The iconic GMC 2-1/2-ton truck does not need an introduction. It still is one of the most recognized vehicles of WW II. This truck was produced in great numbers and many variations of bodies were made. One of these variations were the ST-5 and ST-6 bodied versions. From the TM 9-2800 1943 we see the following:



In this presentation we see an ST-5 bodied GMC with the configuration of the Artillery repair truck M9. In the next picture the ST-5 body is better visible.



One of the first very obvious differences between the ST-5 and ST-6 bodies is the fact that the ST-5 body was non-collapsible. The later ST-6 body was collapsible. The reason behind this was, that the ST-6 body when in collapsed state was taking less space for transport and shipping. The rear double door, the different panels, and the side windows and accessories were removable and could be moved inside the vehicle. Below the opened and collapsed ST-6 body. The most visible difference between the ST-5 and ST-6 were the rows of plates below the windows. So the ones with the plates identifying the ST-6 body. As can be seen in the pictures in this article, the bodies were fitted on closed as wel as on open cabbed GMC's.




 

Details of the ST-5 Body.





Variations of the ST-5 and ST-6 Bodies.

From several Manuals (TM 9-2800 1943 - ORD 9 SNL G-227 1945 - Catalogue of Standard Ordnance Items, Second Edition 1944, Volume 1) The following list of the various ST-5 and ST-6 bodies could be compiled:

- Truck 2-1/2-ton 6x6, Small Arms Repair, M7
- Truck 2-1/2-ton 6x6, Small Arms Repair, M7A1
- Truck 2-1/2-ton 6x6, Small Arms Repair, M7A2
- Truck 2-1/2-ton 6x6, Automotive Repair, M8 (LA and LB)
- Truck 2-1/2-ton 6x6, Automotive Repair, M8A1 (LA and LB)
- Truck 2-1/2-ton 6x6, Instrument Repair, M10 (LA and LB)
- Truck 2-1/2-ton 6x6, Instrument Repair, M10A1 (LA and LB)
- Truck 2-1/2-ton 6x6, Instrument Repair, M10A2
- Truck 2-1/2-ton 6x6, Welding Repair, M12
- Truck 2-1/2-ton 6x6, Welding Repair, M12A1
- Truck 2-1/2-ton 6x6, Tool and Bench, M13
- Truck 2-1/2-ton 6x6, Spare Parts, M14 (LA and LB)
- Truck 2-1/2-ton 6x6, Machine Shop, Ml6 (LA, LB, LB1, LB2, LC, LD, LF)
- Truck 2-1/2-ton 6x6, Machine Shop, M16A1
- Truck 2-1/2-ton 6x6, Machine Shop, M16A2
- Truck 2-1/2-ton 6x6, Electrical Repair, M18
- Truck 2-1/2-ton 6x6, Electrical Repair, M18A1
- Truck 2-1/2-ton 6x6, Electrical Repair, M18A2
- Truck 2-1/2-ton 6x6, Instrument Bench, M23
- Truck 2-1/2-ton 6x6, Instrument Bench, M23A1
- Truck 2-1/2-ton 6x6, Signal Corps Repair M30
- Truck 2-1/2-ton 6x6, Signal Corps General Repair M31
- Truck 2-1/2-ton 6x6, Tire Repair M32 (LA and LB)

LA - LB etc. Means Load A - Load B etc. These bodies with same name but equipped with different Loads, slightly different tool sets.

Length: 3,760 mm.
Width: 2,440 mm.
Height: 2,060 mm.
Volume: 18,0 m3, reducible to 13,4 m3




Scale Drawing of ST-6 Body

And the pictures to complete the view of the vehicle.



These are Mobile Shop Trucks, used for Ordnance maintenance, mounted on the 2-1/2-ton, 6x6 (4dt) truck chassis of 164-in. wheelbase. Bodies are all metal, completely inclosed. The same body is used for all the various models listed above. They differ only in the various tools and equipment mounted or carried within them. So on the outside there are no visible differences notable.

The ST-6 Body is 148 inches long, 96 inches wide, and 81-5/8 inches high, outside dimensions. Six windows are provided on each side, as well as a small window in the front and two windows in the doors. They are all protected by heavy brush guards and screen wire, so as to break up light reflection. Side windows can all be opened and all windows are provided with black-out curtains. A heating and ventilating unit is provided so that the truck can be used under all climatic conditions. In addition a black-out system was installed which automatically switched off light when someone opened the door for reasons of secrecy.

Standard equipment for the various models of the trucks includes a safety ladder for access to the rear of the unit, as can be seen later in this article, and an electric light system having a blackout arrangement which automatically turns off the lights when the doors are opened. The equipment and tools furnished in the various loads are interchangeable to a great extent and are also to be found in common items for shop use. Earlier models of Mobile Shop Trucks used a Model ST-5 Body, which lacked the collapsible feature. They were classified as Limited Standard by the Ordnance Committee action in November 1942 and February 1943.

Known Manufacturers: Hicks Body Company, PA Thomas Car Works, Superior Coach Corp, and Krieger Steel Sections.




As can be seen in the two pictures above, here the ST-6 body was mounted on the open cabbed version. Thus indicating that these bodies were mounted on both chassis types. Here the left sides of the erected and collapsed state are shown.



Details of the ST-6 Body.










Below a picture of a restored GMC with ST-6 body. in this picture the mesh protection screens are lowered, showing the glass windows in the body. I wanted to show this because this is seldomly shown in WW II contemporary pictures.





Small Arms Repair Trucks M7, M7A1 and M7A2
, were intended for inspection, maintenance, and repair of small arms. The benches furnished provide space for the tools and the armorer’s tool kits, and also for kits carrying spare parts for the individual weapons. Common tools, such as a 3/8-in. portable electric drill with stand, electric bench grinder, vises, drill sets, hack saws, hammers, reamers, cleaning rods, gasoline torches, trigger weights, are supplied. The armorer’s tool kits are equipped with common hand tools and also special tools needed in small-arms repair work, such as cartridge extractors and oil stones. A portable rifle rack is furnished for storing rifles under examination or repair. A portable table is also furnished to give additional work space outside the vehicle. Electric power normally is furnished from one of the other mobile shop trucks, but the truck can get its own power from a portable, gasoline-engine-driven generator of 2-k.w. capacity. (ORD 7 SNL G-138 1944 - 1945 - 1946)












Interior inside view of the M7A2.


Below some of the equipment that appears in the pictures above and is mentioned in the text, is shown separately.







Automotive Repair Trucks M8 and M8A1 contained tools and equipment needed for general automotive repair work. It is used primarily by the Air Force for airfield vehicle maintenance. The load consists of such items as general automotive tools, including a hydraulic portable press, drill sets, extractor sets, hammers, pliers, sledge, vises, test sets (both high and low tension and compression), pneumatic nut runner set, pneumatic chisel set, tube vulcanizer, socket wrench sets of various sizes, and automotive mechanic’s tool kits with the individual mechanic’s chisels, files, hammers, screwdrivers, etc. Electric power for this unit is furnished from a combination air compressor and generator engine-driven set. The air compressor has a 60-cu.-ft. capacity. The generator can furnish 5-k.w., 110-v., alternating current. Of this vehicle no pictures are available yet.



Artillery Repair Trucks M9 and M9A1
were intended for maintenance of various artillery items by the Heavy Maintenance Companies. Each truck carries a workbench with drawers, as well as tackle blocks, rope, chain hoists, a 1-ton collapsible tripod, electrical cords and connections, portable electric drill, a vise, and allied equipment. Special artillery tools are added by the using organizations according to their assignments. The artillery mechanic’s tool kits that are furnished include such items as chisels, drifts, files, hammers, punches, screwdrivers, sharpening stones, and wrenches. Electric power is not available within this truck itself but is obtained from another unit within the company. A similar set of equipment, known as “Ordnance Maintenance Set F,” is furnished to Medium Maintenance Companies. This unit is carried in a standard 2-1/2-ton, l.w.b. cargo truck. Below the interior of the M9A1 Truck.





Instrument Repair Trucks M10, M10A1 and M10A2
were intended for repair and maintenance of optical instruments and equipment. For major repair work, a standard 10-in. precision bench lathe, a 1/4-in. precision drill press, a 1/2-ton arbor press, and an electric bench grinder are furnished, Standard tools and equipment include surface plates with leveling screws, mandrel sets, drill sets, drifts, clamps, chisels, tiles, stud extractors, gages, hammers, pliers, reamers, rules, sharpening stones, threading sets (both U.S. standard and metric), vises, and wrenches. Each truck is furnished with several Instrument Repairmen’s Kits. These are equipped with forceps, gravers, hammers, watchmaker's loups, oilers, adjusting pins, punches, scrapers, scribers, special wrenches, etc. A Leatherworker’s Kit is included for repair of the leather cases normally found with optical instruments. This kit has such items as awls, saddler’s carriage, leather creaser, leather knives, needles, suilmuker’s palm, punches, rivet set, and saddler’s tools. Special tools, fixtures, etc. are furnished to the using organizations for this truck in relation to the work assigned. Outrigger jacks are provided to stabilize the truck for the delicate repair operations. Normally this truck obtains its electric power from unother truck or a commercial source. However, it has a 2-k.w., 115-v., a.c., engine-driven generator (portable) that can be set up on the ground so as not to cause vibrations within the truck. Below the M10 with ST-5 body.









Welding Repair Trucks M12 and M12A1.
The Welding Truck M12. The Welding Truck M12 was is a 6 x 6 truck, somewhat larger than the Welding Truck M3 and incorporates certain new improvements. The equipment and accessories are essentially the same on the Truck M12 as for the Truck M3. The main difference being that a 300-ampere arc welding generator was installed, and this generator was driven by a separate gasoline engine instead of through a power take off as on the Truck M3. The Truck M3 had a cab-over-engine bus body. Below the ST-5 body is shown with the mesh window covers removed. Note the pipe mounted on the right front, probably an exaust for the welding generator. See also the M16 Trucks that had a similar construction.








Tool and Bench Trucks M13.
No information of these trucks is available.



Spare Parts trucks M14.
No information of these trucks is available.



Machine Shop Trucks Ml6, M16A1 and M16A2.
These units were intended for basic machine-shop work and are equipped for almost any general kind of machine-shop work encountered in the field. They are all equipped with an engine-driven, 10-k.w., 115/230-v., a.c. single-phase generator set. M16A2, LOAD A. This unit is built around a standard 10-in. bench lathe with complete set of tools and accessories, electric bench grinder, a 7-in. bench shaper, a 10-ton hydraulic press, a milling head attachment for the lathe, and a special 1/2-in. drill press that is very much like a radial drill. A complete set of hand tools, gages, calipers, extractors, drill sets, threading sets (U. S. standard as well as metric), etc., are furnished to complement the basic machine tools. M16A1, LOAD B. This is basically a heavy lathe truck. Load B is equipped with a 14-21-in. gap lathe, as well as a 1-1/4-in. portable electric drill with stand and a drill grinder. A few hand tools and drill sets are furnished with this load to supplement the Load A and to make the lathe as useful as possible. M16A1, LOAD B1. This unit is much the same as the Load B, except that it has a 16-in.-swing lathe and a milling head attachment. M16A1, LOAD B2. This unit is essentially the same as the Load B, except that it has an extension-gap lathe of 14-29-in. swing capacity. The gap can be extended to 19 inches.



Notice the pipe construction on the right front side of the body. Probably installed as an exhaust for the Gasoline-Engine drive Generator, this was mounted at the right front corner of the Body as is evident from the pictures below. The M12 Welding Truck also had a pipe mounted. This exhaust was not standard issue on all ST-6 bodies as is evident from pictures.







Electrical Repair Trucks M18, M18A1 and M18A2.
These trucks were intended for use as a test and repair station for various automotive types of electrical equipment. Its major items of equipment and its tools are an electrical test bench, magneto test stand, magnet charger, and other similar electrical test equipment. Repair tools and equipment include such items asstandard tools, u vise, hammers, chisels, pliers, wrenches, and automotive mechanic’s tool kits. A portable gasoline-engine-driven battery-charging general or is furnished, along with allied test and repair equipment . The unit has its own source of power in a 10-k.w., 115/230-v., u.c., engine-driven generator set.









Instrument Bench Trucks M23 and M23A1.
Were primarily intended to maintain and repair special fire-control equipment, such as antiaircraft directors
and range and height finders. The truck body is ideally suited for this type of work in that the heater vcntilation system is 97% efficient in removing all dust and foreign particles from the air. Essential equipment consists of one bench across the front of the truck and two collapsible tables, which can he used within the truck or set up on the ground. In this manner, considerable space is made available for the setting up of the instruments to he worked upon. A special tripod is furnished for the Directors M5 and M6. Special harnesses are furnished for strapping down the directors should it be necessary to move a truck with the directors inside.Small tools arc furnished, as well as Instrument Repairmen's Kits. A set of outrigger jacks is provided to help stabilize the truck. These units had no power of its own, but connections were furnished so that these could obtain power from the generator normally used with the directors or from one of the other mobile shop trucks. Of this vehicle no pictures are available yet.



Signal Corps Repair Trucks M30.
These units were equipped with a basic set of equipment for issuance to the Signal Corps for their use in repairing various radio, wire, and radar equipment. It is essentially the same as the Signal Corps General Repair Truck M31, except that it has additional equipment, such as a shockproof shelf for carrying the delicate test equipment, a small air compressor for cleaning purposes, a 12-volt battery, a battery charger, and special 6-, 12-, and 24-volt d.c. circuit. Many additional convenience outlets are furnished in order to permit testing and repairing of numerous pieces of equipment at the same time. The unit obtains its electric power from an outside source.







Signal Corps General Repair Trucks M31. These units were equipped with a basic set of equipment for issuance to the Signal Corps for their use in repairing various radio, wire, and radar equipment. It is essentially the same as the Signal Corps General Repair Truck M30 but missing the extra equipent mentioned with the M30.







Tire Repair Trucks M32.
These units consisted of two trucks, Load A and Load B, and two 1-Ton, 2-Wheel, Tire Repair Trailers M25, Load A and Load B. The complete unit is used for sectional tire repair and tube work. LOAD A. This unit carried all of the electric mold equipment, including an electric steam generator, some of the air bags, molds, matrices, and repair equipment. LOAD B. This unit was primarily an inspection and work unit. Its equipment consisted of a bench with tire mandrel and electrically driven air compressor, tire spreaders of three different sizes and types, tube inspection tank, some matrices, bead plates, air bags, and repair supplies and equipment.TRAILER, LOAD A.The trailer loads were carried in the standard 1-ton cargo trailers. This load consists only of a 25-k.w., 115/230-v., a.c., 3-phase, engine-dnven generator set. It furnishes all power needed for the complete unit. TRAILER, LOAD B. This trailer carried additional equipment and accessories needed for the operation of the complete unit. Some of these items are buffing machines, additional matrices, bead plates, air bags, extra gasoline and water cans, supplies, and company equipment. Of this vehicle no pictures are available yet.

Information used from the following sources:

ORD 7 SNL G-138 (1944)
ORD 7 SNL G-141 (1944)
ORD 7 SNL G-146 (1944)
ORD 7 SNL G-149 (1945)
ORD 7 SNL G-229 (1945)
ORD 7 SNL G-235 (1945)
ORD 9 SNL G-227 (1945)
TM 9-2800 (1943)
TM 9-2852 (1943)
Ordnance Maintenance Catalogue (1945)
GMC - A Universal Truck by J.M. Boniface and J.G. Jeudy
Maintenace and Parts Book - Body, Mobile Shop Truck, Collapsible
Type, Model ST-6 from Hicks Body Co. Inc. (1942)



Scale Models
. In the past Azimut-ADV from Paris France produced a resin aftermarket kit of the ST5/6 workshop body. In essence this was an ST-6. wich was clearly visisble because the small plates beneath the windows. This kit is however not available anymore. The website from this firm is down and the firm was deleted from the chamber of commerce of Paris. So i guess Azimut-ADV does not exsist anymore, wich is a shame because they made some nice kits. Another one was from Calibre35. I don't know if this one is available. Sometimes these aftermarket kits are difficult to obtain. As for the 2-1/2-ton 6x6 GMC trucks, there are several choices, from Tamiya, Italeri, Heller, all 1/35th scale.