For 45 Years, Mitsubishi Turned Humble Willys Jeep CJs Into Diesel Off-Roading Beasts

The Willys Jeep has remained a worldwide sensation throughout much of history. Everyone from the military to off-roading enthusiasts has seemingly taken these old-school rigs to the ends of the Earth. Given the red, white, and blue origins of the Willys Jeep, you’d think all the coolest versions were sold in America. And yet, there are very interesting variants we didn’t get. For decades, Mitsubishi took the CJ-3B design and churned out more than two dozen different variations of the world’s most famous off-roader, even giving the iconic 4X4 durable diesel engines for some iterations.

American car enthusiasts looking for a rugged Japanese domestic market four-wheel-drive will discover something pretty weird when they dig into Mitsubishi. In between the sweet 4×4 Delica vans and legendary Pajero SUVs sits the Mitsubishi Jeep. Not “Jeep” as shorthand for a small open-top off-roader, the way someone might say “Kleenex” when they mean “tissue,” but a real Jeep with a Mitsubishi badge. And then you realize these Jeeps also aren’t just rebadged CJ-3Bs, but they have their own lighting, weird body configurations, and an array of diesel engines.

That last part alone is pretty fascinating because, while Jeep had experimented with diesel engines in the CJ in the past, they never really became mainstream. Historically, the beloved CJ was powered by stout gasoline engines, but there’s a big benefit to diesel engines in the field: diesels produce high torque at low RPM, and that’s great for off-roading. You can also modify a diesel run on some alternative fuels, which has appeal to some folks and makes the Jeep even more versatile.

But how did Mitsubishi get its hands on a real Jeep? Why did Mitsubishi then keep making them until about 1998?

A Tough Vehicle For Rebuilding Japan

The origins of the Mitsubishi Jeep actually aren’t as crazy as you might think. According to Mitsubishi, its version of the Jeep came to be during Japan’s reconstruction efforts after World War II. Japan had seen more than just heavy losses to its people, buildings, and infrastructure, but as MotorTrend notes, the war was a huge cultural reset, too. Japan began doing new things and in new ways than before.

Mitsubishi says that the multipurpose Jeep, which had proven itself to be a winning asset in the war, looked attractive to Japan. Specifically, in 1950, the National Police Reserve (today the Japan Ground Self-Defense Force) wanted its own Jeep-like vehicle. However, the Japanese government was protective of its industries, which made the prospect of importing whole Jeeps in high numbers a non-starter. So, the Japanese auto industry did the next best thing. If it could not import high numbers of complete Jeeps, it would just make its own Jeeps.

Japan’s automakers hadn’t been in the business of making cars for very long by that point. Toyota had been making production passenger cars for only 14 years, and while Mitsubishi had more experience, we’re still talking about a span of only 33 years.

Both automakers, which were still rebuilding after the war, answered the call for the National Police Reserve and Toyota began producing the Toyota Jeep (BJ) by 1951. While it was named a Jeep, this off-roader had a chassis based on the firm’s SB-Series 1-ton truck, and its passenger-car-derived Type B gasoline engine was technically a descendant Chevrolet’s Stovebolt engine from the 1930s. Toyota notes that its use of the Jeep name wasn’t exactly kosher, and in 1954, it changed the name of the BJ to the Land Cruiser, a nameplate that itself is an icon today.

Mitsubishi took a different path. Instead of trying to make its own flavor of Jeep, it went straight to the source. From Mitsubishi:

In 1952, Shin Mitsubishi Heavy Industries Co. Ltd. therefore contracted with the Jeep’s manufacturer the American company Willys Overland Motors to import the Jeep CJ3A in CKD (complete knocked down) form. The following year in 1953 the company completed the first knock-down Jeep, the J1, and 54 units were delivered to the Forestry Agency. In July of the same year, MHI entered technology assistance and sales agreements with Willys, Mitsubishi began domestic production of the Jeep. This happened to coincide with Willys switching production from the CJ3A to the CJ3B design and the CJ3B-J3 took its cues from the CJ3B model.

From 1953 forward, the Mitsubishi Jeep was a licensed Jeep product, but built and sold in Japan. Mitsubishi really stretched out the CJ-3B platform, creating over 30 variations over the course of 45 years. The Mitsubishi Jeep came in short, medium, and long wheelbase configurations in addition to a plethora of body styles, including soft top two-door SUVs, hard top two-door SUVs, and up to all-metal enclosed wagons.

The CJ-3B was a pretty interesting platform, too. I’ll let David Tracy take the mic here to educate you on its goodness:

It’s the first Jeep that the world pretty much unanimously decided was “ugly” (but charmingly so), with its hilariously tall grille meant to fill the space between the frame and the new-for-1953 high-hood needed to clear the new “F-Head” engine.

Honestly, the CJ-3B is a bit of an odd duck. We all are pretty familiar with the World War II Jeep; it and its CJ-2A and CJ-3A (all three shown below) successors have a lower hood than my 1954 CJ-3B because under their hoods were “L-Head” engines known famously as “Go-Devils.” The Go-Devil motor made only 60 horsepower, but thanks to a long stroke, it cranked out 105 lb-ft of torque.

David then talks about how Jeep went through the work to develop the Hurricane. I highly recommend clicking here to read more. Anyway, David continues with:

Some Jeep historian is going to have to explain this to me, because I don’t understand what happened next. Willys develops a brand new, more powerful engine and, to fit it, they design a beautiful vehicle with rounded fenders, a cool bulge in the center of the hood, and a less slab-sided profile. But instead of making this vehicle available to the public, they give the sexy Jeep to the military, and what do they build for civilians who want the new Hurricane motor? They take their CJ-3A and slap a tall hood on it, adapt a grille that reaches higher, raise the windshield, and make a few other adaptations that ultimately yield what many considered the ugliest Jeep of all time at that point.

The Mitsubishi Jeep

The original Mitsubishi Jeep J3 (the model name is a reference to the fact that this was the third time Mitsubishi sold a Jeep product; the previous ones were CJ-3As) was really just a barely rebadged Jeep CJ-3B. The J3 featured steering on the left, a doorless and roofless body, and was even powered by a 2.2-liter 69 HP F-head Hurricane four that Mitsubishi had renamed to the JH4. Mitsubishi began producing the Hurricane locally in 1955. These early J3s were extremely basic with three-speed manual transmissions and two-speed transfer cases.

This turned out to be exactly what the National Police Reserve was looking for, as the Mitsubishi Jeep wasn’t an imitation of a Jeep, but the real deal. Thus, Mitsubishi won the contract. Mitsubishi notes that most of its Jeeps were sold to police and military agencies around the world, but they were also sold to the public, too, going up against the likes of the Nissan Patrol and the Toyota Land Cruiser.

The Mitsubishi Jeep went through some fun variations early on in its life, with the introduction of the J10 six-seater in 1955 and the J11 panel wagon in 1956. Amazingly, the Mitsubishi Jeep didn’t even get a right-hand drive model until about 1960.

Diesel power arrived in 1958 with the 2.2-liter Mitsubishi KE31 four-cylinder, which made 61 HP and 97 lb-ft of torque. In the 1970s, Mitsubishi would up the power by bringing on its 2.7-liter 4DR5 diesel four, which made 80 HP and 130 lb-ft of torque.

Military versions of the Mitsubishi Jeep also had access to the 2.7-liter 4DR6 turbodiesel four, which made 135 HP and more than 162 lb-ft of torque in its hottest form with an air-to-air intercooler. The civilian version of this engine made 100 HP and 162 lb-ft of torque.

While many Mitsubishi Jeeps were sold with diesel engines, the marque also sold them with gasoline mills. The Mitsubishi version of the Hurricane was bumped up to 76 HP and 118 lb-ft of torque by the early 1960s. The biggest gas engine was the 2.4-liter 4G53 four, which made 110 HP and 144 lb-ft of torque.

America Takes A Peek

These diesel Jeeps were alluring enough that, in 1966, the U.S. Army Tank-Automotive Center in Warren, Michigan, shipped some Mitsubishi Jeeps to America to test how the diesel power changed the character of the CJ-3B. In America, the Jeeps arrived at the Keweenaw Field Station of the Keweenaw Research Center of Michigan Technological University.

The Jeeps were torture tested at the station, but were also put onto public paved and secondary roads. The U.S. military noted that these Jeeps were identical in almost every way to American Civilian Jeeps, but were equipped with Mitsubishi’s KE31 diesels. What’s neat about the military testing is that we get to learn more about the Mitsubishi Jeep, including the fact that the military version had a governed top speed of 55 mph.

These tests weren’t necessarily easy, either, as the researchers subjected the Japanese Jeeps to 550 miles of cross-country driving, 200 miles on unpaved secondary roads, 200 miles on paved roads, and 50 miles in mud. The testing started in the fall and ended in the winter, which meant that the Jeeps had to do all of this while running through rain and snow.

The abstract of the research concluded with:

The overall performance of the vehicle compared favorably with the American version of the Jeep. The Diesel engine gave it better economy, although it was more sluggish, and the engine noise was somewhat objectionable on longer duration runs. No significant maintenance problems were encountered.

The results were impressive, showing that the Mitsubishi diesel Jeep could climb a 70 percent grade, drive on side slopes of 35 degrees, and achieve fuel economy as high as 25.4 mpg on pavement. Of course, there’s some context needed for the fuel economy number: the Jeeps were run at 45 mph. The researchers noted the engine in the Mitsubishi Jeep failed, but the damage happened during shipping to Michigan. The failures were weird, too:

Basically, the difficulty was that the cap screw which holds the drive gear on the camshaft worked loose and allowed the camshaft to shift rearward in its bearings. As a consequence the cam lobes no longer were in proper alignment with the valve lifters and caused the latter to break.

Using a longer screw fixed this issue. Aside from the shipping mishap, the test Jeeps covered 6,219 miles, with the worst real problem being one dead starter.

Mitsubishi Jeeps did go into service with the U.S. military, but on offshore bases.

The Mitsubishi Jeep Made A Cultural Impact

The Mitsubishi Jeep also became a bit of a sensation with the off-roading public. Brochures for the Mitsubishi Jeep show CJ-3Bs in fabulous color schemes, and the marketing copy talks about how Jeep has been a rugged icon since 1941. Curiously, the advertising doesn’t talk much about Mitsubishi at all, and instead leans on how cool Jeeps are.

The Mitsubishi Jeep became such a sensation in Japan that Mitsubishi began publishing hype magazines for Mitsubishi Jeep owners of all kinds.

I’ve also noticed Mitsubishi Jeep love is spread around the world. Punch “Mitsubishi Jeep” into the Internet Archive and you’ll find several books and novels from international authors that feature Mitsubishi Jeeps in action. In a way, the Jeep CJ-3B and its derivatives, including the Mitsubishi Jeep, were probably a better ambassador for the Jeep brand than any other classic Jeep.

The Mitsubishi Jeep was, at least, beloved enough to keep it in production for  45 years, making it the longest-lasting Jeep model. Mitsubishi built over 200,000 examples over the decades and says that the only reason why it had to stop after 1998 was due to tightening emissions and safety regulations that its 1950s-based design could no longer meet.

Today, the Mitsubishi Jeep is somewhat of a collector’s item. Examples in mint condition could easily cost you more than $20,000. More well-loved examples can easily be found in the Japanese auction system for $3,000 and under. You should be aware, however, that countless Mitsubishi Jeeps have lived hard lives and have the rust, missing parts, and decay to show for it. Seriously, some of these look like they could have been parked at David’s old house in Detroit.

That’s probably why sellers of really nice examples often ask top dollar for them. If you want your own diesel CJ-3B with a diamond badge on it, I would recommend reaching out to an auction agent or an importer. I have used the Import Guys and Japan Car Direct to great success. You can also find Mitsubishi Jeeps for sale at Japanese export platforms like Car From Japan or Be Forward, as well as some dealers here in America.

The Mitsubishi Jeep is one of those stories where something weird was born out of necessity, but then sort of became its own thing. For decades, Japanese off-road enthusiasts and even the military loved scooting around in America’s favorite 4×4, but built right there in Japan with a homegrown diesel engine. The fact that it then remained in production for so long is also impressive. So, if you want a Jeep CJ-3B, but slightly different, maybe your next stop might be Japan.

Top graphic image: Mitsubishi