Mercedes-Benz Unimog U 5023 2022 Review

These days, there are too many vehicles that attract superlatives. Terms such as iconic, legendary, illustrious; they’re bandied around and handed out willy-nilly. But when it comes to off-road trucks, and indeed off-road vehicles of any kind, the Unimog fits the bill and is deserved of any and all accolades.

The Unimog, which is a shortened version of Universal Motorised Gerat (Gerat meaning machine or piece of equipment in German) was initially designed shortly after the Second World War but popularised in the 1950s and 1960s.

It was initially manufactured by Boehringer as a smallish agricultural tractor but was taken over by Daimler-Benz in 1951 and lengthened, given a proper cab and repowered to resemble something along the lines of what we have today.

Considering all the technological and design advances we’ve made over the past half-century, the Unimog has changed little. It still has its angular, even boxy appearance, but unlike some other off-road vehicles the Unimog has lost none of its ability. In fact, if anything, it has gained ability and certainly comfort levels.

Today’s ’Mog

These days, the Unimog is powered by a modern 5.5-litre four-cylinder turbo-diesel engine that has outputs of 170kW (231hp) and, more importantly, 900Nm of maximum torque that’s produced between 1200 and 1600rpm.

The transmission is interesting in that it offers eight forward gears and six reverse gears. Then there’s a two-speed transfer case offering four-wheel drive and a low ratio of 3.19:1, which means there’s a total of 16 forward gears and 12 reverse gears on offer.

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It’s interesting to note here that with a first gear ratio of 9.57:1 and an axle ratio of a low 5.92, the final reduction in first low is a stunning 180:1. Just for comparison, the final reduction in first low in a Toyota HiLux is around 32:1.

Add to that the Unimog’s selection of three diff locks, a 1.2-metre wading depth, 500mm of ground clearance and absolutely extraordinary approach, departure and ramp-over angles, and you have one seriously capable off-road vehicle.

Australian Unimogs are fitted with 395/85R20 Michelin X tyres which are a chunky off-road design that provides plenty of grip for mud, snow and rocky terrain.

According to Jimmy Dalgleish, Product Manager at Mercedes-Benz Special Trucks, most of the ’Mogs that come into Australia are fitted with the automatic tyre inflation system which, at the press of button, will set your tyres to the correct inflation for the load you’re carrying and the terrain you’re encountering.

We used this fantastic feature on our test run and it was brilliant! You simply dial up the system via a push-button and it shows up on the info screen on the dash. It sets up prompts so you can let it know if you are empty, have a half load or a full load, then the type of terrain you are on: Highway, Cross Country, Sand/Mud/Snow and Emergency. Once you’ve entered those parameters, it will inflate or deflate the tyres to suit.

At one stage, I had the tyres down very low to attempt a very steep and muddy hill climb. I then switched out of low range to do some mud runs on the flat. After one run, I decided to reinflate the tyres only to find that the Unimog had done it for me because I’d shifted out of low and increased my speed!

Jimmy said that one of his biggest customers, the Victorian Department of Environment, Land, Water and Planning (DELWP), always specifies this feature on its Unimogs.

Getting serious

Our day out in the Unimog was mostly spent at the Melbourne 4x4 Training and Proving Ground, which we’re fairly well acquainted with. It provides plenty of tests for off-road vehicles including water crossings, mud, steep climbs and descents and a variety of suspension tests.

Climbing proved no problem for the Unimog. With its combination of low gearing, grunt and the Michelin off-road tyres, it got up everything we threw at it. A couple of times I had to back off and readjust the settings of the vehicle but I got up with little fuss.

Over the suspension tests the Unimog had no problem either mainly due to its remarkable wheel articulation and ground clearance.

The wheel articulation is aided by extra-long-travel suspension and by the fact that the whole vehicle can twist. All the components of the Unimog are mounted so that they can move independently of one another and allow the vehicle to move about itself. Even the engine and transmission are mounted separately and joined by a shaft so they can move.

Ground clearance is enhanced by what I would call drop axles, but Mercedes-Benz calls them ‘portal axles’. With this setup, the axles are higher than the centre of the wheel and gears drop down to drive the wheels leaving the axles and diffs higher than they would normally be if the axles ran directly into the centre of the wheel.

The whole drivetrain from front to rear is enclosed with the drive shafts running through ‘torque tubes’. This protects them from contamination through dust, water and other off-road nasties.

Both the exhaust and air intake are high. Very high. And the alternator sits high and protected in the engine bay. This gives the Unimog its 1.2-metre wading depth. Our foray into the river didn’t even get close to testing its limits.

Is the Unimog hard to drive?

From a driving perspective, the Unimog can be as simple or complex as you want. The vehicle can be driven in full auto mode, or press a stalk-mounted button and it’s in manual mode.

Want a clutch? No problem. Simply pull a lever and out pops a clutch from a hiding spot near the firewall. Now you’ve got a full manual, with clutch, and gears manually selected by pulling or pushing the right-hand stalk.

In our off-road sections I drove in manual mode without the clutch. When attacking a gradient either up or down, I simply selected the gear I wanted before taking off – mainly second or third low – then let the vehicle do its job. If I needed any more engine braking then there’s also a two-stage retarder that works just like a Jake brake.

On our road section, I drove in full-auto mode and it was a breeze. The comfort levels in the cab are high for what is ostensibly a utilitarian vehicle. There are suspension seats for the driver and front passenger, air-conditioning, cruise control, electric windows, in fact most of the mod cons you get in a normal truck. And it’s surprisingly quiet on the road.

Sure you get a bit of tyre noise from the chunky Michelins, but it is really not a bad environment to travel in.

On the highway the Unimog will do 100km/h without much trouble but it’s happiest at around 90-95km/h.

It steers, brakes and handles just like a normal truck, although I admit that I didn’t get it on any really twisty bits – that’s not what this test was all about.

Is the Unimog expensive?

In a word, yes. Jimmy Dalgleish told us that they start at around $225,000 but that’s for a bare-bones single-cab vehicle. Add the double-cab, the tyre inflation system (and who wouldn’t want that!) and a few other necessities and the price rises rapidly.

But what you’re getting is a truck that’s virtually hand built in the factory at Worth in southern Germany and backed by the might of the Daimler Trucks corporation.

Certainly they’re not for everyone but for the off-road enthusiast or trucking operator who wants or needs something bigger than a ute or a four-wheel drive light truck for serious off-road work, the Unimog is at the top of the heap.

Final thoughts

What a great day. We don’t often get to drive a vehicle like the Unimog, but having done so for a day has confirmed my belief that this is truly an iconic vehicle. To have changed so little in the past half-century or more means that ’Benz got the formula right from the start and has merely refined it as the years have rolled on.

I would love to have another drive of a Unimog as I know that the more you get acquainted with these trucks, the better you can drive them. Getting the air pressures right, selecting the right gear, getting the revs right… when it all comes together, it’s just off-road bliss.

Can I have another go? Please?

Specifications:
Mercedes-Benz Unimog U 5023
Engine: OM 934 LA 5.5-litre four-cylinder turbo-diesel
Max Power: 170kW (213hp) at 2200rpm
Max torque: 900Nm at 1200 to 1600rpm
Transmission: UG 100/8 eight-speed automated manual, two-speed transfer case
Suspension: Coil springs with hydraulic dampers
Axles: Troque tube linked portal axles
Axle ratio: 6.94:1
GVM: 14.1 tonnes
GCM: 32.5 tonnes
Tyres: 395/85R20 Michelin X
Fuel capacity: 235 litres
Turning circle: 16.6 metres
Approach angle: 44 degrees
Departure angle: 51 degrees
Breakover angle: 30 degrees
Fording depth: 1.2 metres