Unimog Goes Everywhere, Does Almost Anything

By Tom Berg, Truck Editor | September 28, 2010

Unimog 500
Only a German mother could love Unimog's blunt nose, but imagine the visibility out that huge windshield. the cab is made of carbon fiber, and the aluminum-sided body dumps three ways.
Unimog 500
This ditch is nothing for the sure-footed U500, with its full-time all-wheel drive, high ground clearance and locking differentials. Reduction gears in wheel hubs allow use of high-slung portal axles.
Unimog 500
Salesman Troy Adams slides the VarioPilot steering gear, foot pedals and instrument panel to the right-hand position. No controls are disconnected and it takes only a few minutes.
MBE900
Tilting the cab takes a while, but allows full access to engine, transmission and PTO equipment. The MBE900 diesel makes 230 or 280 horsepower; this one's a 280.

Test Set

Truck: Mercedes-Benz Unimog 500, cab-over-engine, all-wheel-drive implement carrier, GVW 33,000 lbs.

Engine: MBE900, turbocharged, intercooled, inline-6, 280 hp @ 2,300 rpm, 800 lbs.-ft. @ 1,250 rpm, w/compression and exhaust brakes

Transmission: M-B Telligent semiautomatic, 8 speeds forward, 6 reverse, w/Low and Low-Low ranges and lockable single-speed 1-to-1 transfer case

Axles & suspensions: M-B hub-reduction, solid portal, axle-link w/locking differentials and 5.92 overall ratio (2.182 in axle diffs, 2.714 at hubs), on coil springs w/15-in. vertical articulation

Wheelbase: 154 inches

Tires & wheels: Michelin XZY 395/85R20 on Accuride two-piece steel discs

Fuel capacity: 60 gallons

Body: Mercedes-supplied 12-ft. utility bed w/drop aluminum sides and 3-way dump capability


How many specialty trucks does a construction, utility or municipal fleet need to do the many jobs expected of it? Maybe all it needs is one: the unique Unimog, built in Germany by DaimlerChrysler. It's a go-anywhere truck and tool-toting tractor, and it'll also fight fires, carry military troops and weapons, and many other things. You may not need its do-anything abilities, but if you're into four-wheelin', you must find a Unimog dealer and drive one.

The Unimog's roots go back to post-World War II Germany, when occupying Allied forces okayed its continued development as a road-capable farm tractor. In 1946, an engineer on the project coined its acronym name, from UNIversal-MOtorGerät, meaning universal power unit.

The original model, the U-25 with a 25-hp Mercedes diesel engine, entered production at a machine-tool manufacturer's factory in 1948. It was a light truck rated at just under 7,000 pounds, less than a fourth of the gross-weight rating of the model now being sent here.

Daimler-Benz (now DaimlerChrysler) acquired the Unimog in 1951. Aside from agricultural work, the nimble truck soon joined the newly formed German Army. It also became a handy vehicle for fire departments, highway crews, and utility and construction operations. It grew in power, size and weight ratings, and was exported to many world markets, including the United States for a while in the 1980s. It now has a cult following with an active market for parts.

Freightliner LLC, owned by DaimlerChrysler, reintroduced the Unimog in 1999. Plans to import the largest of current models, the U500, were delayed by the company's financial difficulties, but now vehicles are coming in and a retail network is being set up. A growing number of Freightliner, Sterling, Western Star and American LaFrance dealers sell U500s with a Unimog nameplate.

Among the dealers is Duthler Truck Center in Wyoming, Mich., a suburb of Grand Rapids. Troy Adams, its Unimog manager, said he looked into using an earlier model on the family farm. "That's how I got interested in them," he said, and he's become a believer in the vehicle and what it can do.

Adams drove our featured truck to the Bosch Proving Grounds west of South Bend, Ind., so I could have a go with it. It was a blast, but in a few hours of buzzing around the grounds, I only scratched the 'Mog's capabilities.

From the pictures you might think the Unimog is a cute little truck, but it's a full Class 7 vehicle meant to carry heavy power tools and a load of hay, dirt, gravel or whatever. Its chassis sits high, so there's a brisk climb into its cab. Once there, the view is truly commanding, and once underway there's a surprising and reassuring feeling of stability. With nicely upholstered suspension seats and air conditioning, it's also amazingly comfortable for something that will work so hard and get so dirty.

Adams quickly explained how to drive the Telligent 8-speed semiautomatic transmission: The selector paddle has D, L and R positions, and you can guess what they do. But before you select one of them you have to punch the clutch pedal. Then engage the clutch and as it begins moving, give it some gas. Each time you want to up- or downshift, tap the paddle and punch the pedal. Tap the paddle forward and punch the clutch to upshift, tap it backwards and punch the clutch to downshift. Got it?

It's easy, and in almost no time I was scurrying around ably. A gear change takes under a second and I was always in control of what the transmission was doing, yet I didn't have to row a gearshift lever.

The diesel is the same MBE900 you'll find in many Freightliner-family trucks these days. It's an electronically controlled, turbocharged and aftercooled, inline-six that makes 230 or 280 horsepower in the Unimog. You can check its fluids through a panel in the vehicle's nose, or tilt the cab with a hand pump (it takes a lot of strokes to raise it, but Adams did the work) to bare most of it.

Because the Unimog is a noseless cabover, visibility out the huge windshield and big side windows is as good as it gets, especially when you're cresting hills.

Though the Unimog is primarily an off-road vehicle, it'll cruise quietly at 70 mph or better. The speedometer and tachometer said 71 mph and 2,200 rpm on the oval test track, and there were another 300 revs left before redline. We also ventured onto nearby highways and county roads, where the ride was smooth and quiet and steering was precise.

Off road, it'll go as slow as you want, thanks to deep-reduction gear sets. Standard is a Low range, engaged by a rocker switch on the console near the transmission selector. In Low, top speed in 8th (top) gear was about 13 mph, and 1st gear barely wobbled the speedo's needle. But wait—an optional Low-Low range gears things down so much that top speed in 8th was 3 mph, and in 1st gear the forward motion is almost imperceptible.

"You can walk faster on your finger tips," Adams said of Low-Low 1st. Why would you need such a capability? I asked. "For operating certain tools, like a concrete cutter," he explained.

Talk about multitasking: Properly outfitted, a Unimog will plow snow, mow grass, trim trees and hedges, drill holes, set poles, raise and position a man-bucket, dig ditches, scoop and lift building materials, hammer or sweep pavement, and so on. Tools are easily mounted and detached, and can be powered mechanically, hydraulically or pneumatically.

On this truck, a front power take-off shaft jutted out ahead of the grill; a rear PTO is also available. This truck had a four-valve hydraulic pump with four output and return points in front and two in back. In this respect, a Unimog can be extensively customized to a customer's needs.

Operations like street sweeping are best done with right-hand drive. Unimog makes it so with an apparatus that lets the driver quickly slide the steering gear, instrument panel and foot peddles from the cab's left side to its right and back again. The optional "VarioPilot" requires no disconnecting of controls; only a central plastic panel needs to be temporarily snapped free of the dashboard and the mirrors readjusted. This body is a three-way tipping flatbed with aluminum sides. Sides are bottom-hinged for dumping loads and easy access to the bed; the tailgate is top hinged. Pivots are easily set for discharging a load out the back or either side—something common in Europe but not in America.

"You could haul a load of dirt or gravel in this," Adams said, "but it's not meant to be a full-on dump truck. It's a utility body."

Because it will run so many types of implements, a Unimog can replace several specialty trucks in a municipal or utility fleet, he noted. And it'll take the tools, a load and a crew of up to three people into and out of places that few other trucks can get to.

Driving impressions

Unfortunately, there weren't many places on the Bosch Proving Grounds that I could prove the 'Mog's abilities. I did trundle diagonally over a deep ditch, where the vehicle got hung up as two opposite wheels spun. But not for long, as I engaged the interaxle differential, then locked one of the axle diffs, which sent power to the wheels and pulled us right out.

I also barreled over some dirt trails in the woods, but never needed the all-wheel drive that was nonetheless always on tap. In fact, I was chasing a Chevy Astro van, of all things, driven by Gary Holse, who heads Freightliner's test operations here. He drove fast but couldn't get away, once I got a feel for the Unimog's cornering ability. This also showed off the Unimog's smooth-acting coil-spring suspension. Anyway, this is a serious on/off-road vehicle, and is more versatile than any other construction truck I've driven.

Unimogs aren't cheap. In late July, Adams said he was close to finalizing his first sale. He was dealing with a logger who'd use a crane-equipped U500 as a forwarder, lugging timber out of the woods and stacking it for pick up by semis. It'd replace a $200,000 machine that sits idle much of the time. The Unimog would cost perhaps half that, and will also plow snow and do other jobs. Looked at that way, the 'Mog is as economical as it is capable—and fun.

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