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The History of Military Jeeps - Military Brats

Posted in Project Vehicles on January 1, 2009 Comment (0)
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Photographers: Jp ArchivesCourtesy Chrysler and LLC.

Everybody loves a military jeep. The thing is, not everybody can distinguish between them. Some people think every jeep driving down the road was once in the military. Others can tell the difference between a GPW and an MB by smell alone. But most folks fall somewhere in between.

It all began in 1940, when the Bantam Pilot was delivered to the US Army for consideration as a light 4x4 reconnaissance and scout vehicle. Powered by a 45-horse Continental four-cylinder engine and with a curb weight of 2,030 pounds, the little Bantam Pilot and 69 subsequent Bantam BRC-60 prototypes whetted the Army's appetite and proved the viability of the concept. An open bid was issued and ultimately Willys, Ford, and Bantam slugged it out with prototypes of their own.

The year 1941 saw production of "pre-standardized" jeeps from all three manufacturers. Ford cranked out roughly 4,458 GPs, Bantam with 2,605 BRC-40s, and Willys with 1,555 MAs. It was from the strengths of these three pre-standardized vehicles that the Army developed its criteria for its "standardized" jeep, which Willys would build during the remainder of the war as the MB and Ford would build as the GPW. The smaller Bantam company would build the trailers towed into combat by the little 1/4-ton vehicles, as well as other parts and components for the war effort.

And from there it was mostly uphill for the military jeep. Up until the late '80s and early '90s, the military kept a fleet of Jeep vehicles for any and all sorts of duties. Even today, foreign countries welcome the Jeep as part of their armed forces. It's the little horse that just keeps on fighting. Here are some of the more common models, how to identify them, and a few key highlights.

1941-1945 Willys MB
Key features that set the Willys MB apart from its GPW cousin are a tubular front crossmember and a flat toolbox lid in the rear fender. The GPW models had a C-channel front crossmember and ridges on the tool box cover. Early '42 models will also have Willys stamped on the rear of the tub and no glovebox in the dash. Either MB or GPW identification is easy, as the grilles have 9 slats, not 7, and smaller headlights that can be pivoted towards the engine for nighttime repairs..

MB Specs
Engine: 134 cube, four-cylinder Go-Devil L-head enginePower: 60hp @ 4,000rpm; 105 lb-ft @ 2,000rpmTransmission: Warner Gear T-84Transfer Case: Spicer 18, 1.97:1 LowFront Axle: Dana 25, 4.88 gearsRear Axle: Dana 23-2, 4.88 gearsWheelbase: 80 inchesCurb Weight: 2,315 lbsHighlights: Nimble, highly sought after, full floating axleshafts, shovel indents on driver side, headlights flipped backwards to work on engine at night, tons of character.Lowlights: Transmission somewhat weak, 9-inch brakes, small 3/4-inch t-case intermediate shaft, rock hard seats.

The 134 Go-Devil delivered 60hp, which by 1941 standards was pretty good considering Ford's popular V-8 flathead only cranked out 85hp. This particular model was rejuvenated after sitting in a field for years. Ease of maintenance was a big selling feature for the MB and GPW, although both were sometimes plagued by carburetor troubles. If needed, an L-head can be rebuilt in the field without removing the engine by dropping the oil pan and removing the cylinder head.

1942-1945 Ford GPW
Aside from the differences between the MB and GPW as mentioned above, other ways of quickly identifying a WWII flattie are the rear wheelwell toolboxes, possibly a machine gun mount on the floor, a fuel tank bulge that protrudes past the rocker of the tub on the drive-side, driver-side shovel and pioneering tool indents, and a passenger-side glove box in the dashboard. Also, early GPWs featured a Ford "F" script stamped into the driver side rear tub as well as F-stamping on many individual parts from pintle hooks to even bolt heads.

GPW Specs
Engine: 134 cube, four-cylinder Go-Devil L-head enginePower: 60hp @ 4,000rpm; 105 lb-ft @ 2,000rpmTransmission: Ford Model GPW-7000 (copy of T-84)Transfer Case: Ford Model GPW-7700 (copy of Spicer 18), 2.46:1 LowFront Axle: Ford Model GPW-3001 (copy of Dana 25), 4.88 gearsRear Axle: Ford Model GPW-4001 (copy of Dana 23-2), 4.88 gearsWheelbase: 80 inchesCurb Weight: 2,315 lbsHighlights: Nimble, highly sought after, shovel indents on side, full floating axleshafts, headlights flipped backwards to work on engine at night, tons of character.Lowlights: Transmission somewhat weak, 9-inch brakes, small 3/4-inch t-case intermediate shaft, rock hard seats.

1950-1952 M-38
While the WWII-era jeep may be the quintessential flattie in the minds of many collectors, the M-38s are held in high regard by Jeep aficionados everywhere. Built from the CJ-3A civilian Jeep, the militarized M-38 featured upgraded drivetrain components compared with the earlier WWII flatties. There were lots of niceties not found on the CJ-2A and CJ-3A civvy models, like a closed, pressurized vent setup that prevented water intrusion to the diffs, drivetrain, and electrical system, a glove box in the dash, protective headlight guards, and in what would become the standard for the military, a 24v electrical system. Unlike the WWII flatties, the military M-38s had the pioneering tool indents on the passenger-side.

M-38 Specs
Engine: 134 cube, four-cylinder Go-Devil L-head enginePower: 60hp @ 4,000rpm; 105 lb-ft @ 2,000rpmTransmission: Warner Gear T-90Transfer Case: Spicer 18, 2.46:1 LowFront Axle: Dana 25, 5.38 gearsRear Axle: Dana 44, 5.38 gearsWheelbase: 80 inchesCurb Weight: 2,750 lbsHighlights: Tons of cool gizmos, much stronger drivetrain than MB/GPW, better gearing, front and rear Power-Loc limited slips in Marine versions. Some rare models affixed with PTO winch on front bumper.Lowlights: Versions with full tops not very common, rear shafts are weaker two-piece 10-spline variety found in civilian flatties, 9-inch brakes.

1952-1957 M38A1
With what would eventually become the CJ-5 and one of the most long-lived vehicle designs of all time, the M38A1 ushered in the age of the round fender Jeeps. Although it sported a militarized 72hp F-head engine like those found in the CJ-3B civilian Jeeps, most of the drivetrain components remained the same as its M-38 predecessor. What the A1 offered over the M-38 was a bit more interior room, a factory shackle reversal front spring setup, an extra 6 inches of fording depth (to 36 inches), an inch of wheelbase (81 inches), and 3 gallons of fuel capacity (17 gallons). Otherwise, the M38A1 actually offered slightly less gross vehicle weight capacity (3,865 pounds versus 3,950 for the M-38) and worse approach and departure angles.

You can distinguish the M38A1 from a civilian CJ-5 from its dog dish indent on the passenger-side cowl, its driver-side dashboard glove box, and its functional battery box door in the top, passenger-side cowl. Other differences are the sunk-in headlights and lack of headlight trim rings, small military black out lights, a factory shackle-reversal, and a large fuel filler cap on the driver side.

M38A1 Specs
Engine: 134 cube, four-cylinder Hurricane F-head enginePower: 72hp @ 4,000rpm; 114 lb-ft @ 2,000rpmTransmission: Warner Gear T-90Transfer Case: Spicer 18, 2.46:1 LowFront Axle: Dana 25, 5.38 gearsRear Axle: Dana 44, 5.38 gearsWheelbase: 81 inchesCurb Weight: 2,660 lbsHighlights: Cool looking grille and two-piece windshield, shackle reversal setup, lots of military trinkets like tow hooks and waterproof drivetrain/ignition setup.Lowlights: Factory 9-inch brakes, dual battery setup placed one in the cowl and one under the hood for some wasted space, easily mistaken for pedestrian CJ-5.

Oddballs and Weirdoes
There are just too many models to give full stats on each. You may have heard about the CJ-10A 2WD airport tug, but how many know about the M-677 crew cab forward control powered by a three-cylinder Cerlist diesel? Or how about the '42-'43 GPA, aka the Seep? It was a flatfender chassis with a sealed hull body that could navigate water like a boat. Or the MB-L, an ultra-light flatfender built with a largely wooden body for light weight and to conserve valuable wartime reserves of steel? There's some wacky stuff out there, so please forgive us if you don't see your pet military jeep or Jeep.

1953-1957 M-170
Adding 20-inches of wheelbase length onto the M38A1's chassis, the 101-inch M-170 was designed as an ambulance and litter carrier with an extra-wide passenger-side door opening and a tailgate. The M-170 enjoyed all of the military drivetrain trinkets and offerings as the M38A1, but was also available in a rare dual rear wheel version. You don't stumble across an M-170 every day, but the wide passenger side door opening makes it easily distinguishable from the CJ-6 civilian models. Otherwise, identify the M-170 by the same shackle reversal, cowl battery box, and other components found on the M38A1.

M-170 Specs
Engine: 134 cube, four-cylinder Hurricane F-head enginePower: 72hp @ 4,000rpm; 114 lb-ft @ 2,000rpmTransmission: Warner Gear T-90Transfer Case: Spicer 18, 2.46:1 LowFront Axle: Dana 25, 5.38 gearsRear Axle: Dana 44, 5.38 gearsWheelbase: 101 inchesCurb Weight: 2,963 lbsHighlights: Wide door opening for family use, 101-inch wheelbase, slightly higher collector value.Lowlights: Factory 9-inch brakes, dual battery setup placed one in the cowl and one under the hood for some wasted space, overall bulk makes it a poor performer with the stock engine.

1967-1969 M-715
Looking to fill the military's need for a 1 1/4-ton hauler to replace its fleet of aging M-37 vehicles, the Kaiser Corporation militarized its J-truck platform and the M-715 was born. With huge 1.5-inch, 23-spline shafts in the rear Dana 70, a decent closed knuckle 30-spline Dana 60 front, a T-98 transmission, and a durable NP-200 t-case, the M-715 could possibly be the burliest Jeep ever produced. Interestingly, most of the M-715's highlights also point out its lowlights. The 5.87 gears in the 5/4 ton axles give the M-715 incredible pulling power and good crawling abilities, but at normal road speeds the "Tornado" OHC 230-cube inline six-cylinder engine can over-rev and come apart. Also, the huge payload afforded by the thick spring packs meant flex was virtually non-existent and harsh doesn't begin to describe the ride.

Despite these drawbacks, the M-715 offered a heavy-duty bed, generous fender flares flanking massive wheelwells, a fold-down windshield, and a removable top. Like other military vehicles of the day, it sports 24-volt electrics, a waterproof drivetrain and electrical system, and standardized components. So a replacement headlight switch for a '90s Hummer fits right in. There's also an M-725 ambulance version with an integrated, enclosed body and a windshield that doesn't fold down.

Engine: 230 cube, six-cylinder Tornado engine Power: 132hp @ 4,000rpm; 198 lb-ft @ 1,700rpm Transmission: Warner Gear T-98 Transfer Case: NP200, 1.96:1 Low Front Axle: Dana 60, 5.87 gears Rear Axle: Dana 70, 5.87 gears Wheelbase: 126 inches Curb Weight: 5,500 lbs Highlights: Excellent 6.39:1 First gear in the T-98, huge Dana 70 rear, decent Dana 60 closed knuckle front, 13x2.5 inch drum brakes, cool body with fold down windshield and neat grille guard, cheap to buy. Lowlights: Enormously harsh ride, underpowered, under revving engine, closed knuckle front axle (arguable), weird 6x7.25 bolt pattern.

Military Jeep Inforama
We didn't just pull all this information out of thin air. As usual, our source for historical Jeep facts and figures is Jim Allen's Jeep Collector's Library published by Motorbooks International. It's an invaluable tool for anybody into old military or civilian Jeeps and covers tech specs on every model up through the TJ and WJ. But if you're allergic to paper, here are a few web sites you may want to visit

TheCJ2Apage.com - vintage civilian Jeeps with some military coverage. earlyCJ5.com - vintage civilian Jeeps with some military coverage

G503.com - heavy early military jeep coverage

M715zone.com - heavy M-715 and M-725 coverage

Steelsoldiers.com - heavy military vehicle coverage including smaller stuff, but specializing mostly 11/4-ton and larger

Willystech.com - vintage Jeep coverage with some military

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