Three Daimler trucks on an expedition through the Tunisian Sahara.

The desert is a place of extremes. Here, both humans and technology alike have to fight harsh conditions. For Marie Trappen, firefighter and off-road enthusiast, the Sahara became a testing ground for her courage, team spirit and the robust Unimog U 4023.

From the fire station to the sand dunes.

When it comes to large vehicles and challenging terrain, Marie Trappen is a real pro: she lives her passion for technology as a machinist with the Kirchhain volunteer fire service. She gained her off-road experience on expeditions for her former employer 4Wheel24, who builds expedition vehicles from old fire-fighting vehicles.

In 2024, she once again chose to follow her adventurous spirit back to Tunisia. This time, she was joined by five friends and three off-road vehicles: the Unimog U 4023, a Mercedes-Benz NG 2028 and a Mercedes-Benz NG 1222.

Well kitted out from Marburg to Tunis.

Her travel companion Carsten had equipped the Unimog U 4023 with additional tanks, enabling the truck to carry an additional 250 litres of diesel and 250 litres of water... so they were perfectly equipped for a journey alone through the desert! “What this vehicle can do is really impressive”, says Marie Trappen.

From Marburg, the route took them to the ferry from Genoa to Tunis. After three days of travel, the adventure began in Tunisia with trips through olive groves and rocky deserts, before they finally reached the sandy desert.

Sandy tests.

When the travellers reached the Sahara, they were rewarded with wonderful expanses of sand and impressive silence. Here, both man and machine were put through their paces: the team had to overcome challenges such as navigating through high dunes, narrow passages and soft sand. “Even when you're driving for a whole day, you never get very far because you have to constantly look for new routes and you get stuck again and again”, says Marie Trappen.

A highlight of the trip was the four-day crossing of the Sahara to the Tembain table mountain. With sand dunes towering up to 50 metres high, the team had to use all of their concentration and teamwork skills in order to reach their destination. The Unimog's tyre pressure control system, which allows you to adapt precisely to the respective surface, was always very helpful.

Service not downtime.

The morning of the third day in the Sahara saw the first challenge to be mastered: it was impossible to engage a gear in the Unimog and the engine made unusual noises. Without a mechanic on hand, the situation became critical. Fortunately, Jan came to the rescue! Using his Starlink internet connection, the team was able to contact a Unimog expert, who asked them to record various sounds, pictures and videos of the Unimog – and he then shared them across the various networks.

Shortly afterwards, Michel Kaiser, department manager at the Unimog Club Gaggenau for the MB-trac division, located in Munich, where the Unimog service conference was taking place, got in touch. He immediately made contact with a service technician from the plant who is very familiar with the internal workings of the Unimog 4023. He was able to assess exactly what the problem was: the transmission had to be taught in again. Following instructions that were given remotely, Marie's friends Oliver and Thomas got to work. Successful: after a one-and-a-half-hour-long procedure in the scorching heat, the Unimog was up and running again, and the team was able to carry on.

But the other two trucks were also put to the test in the desert. The three-axle truck struggled with the unpredictable nature of the terrain: during a manoeuvre in a sand dune, it lost the necessary support surface, so one side ended up hovering in the air while the other sank into the sand. Just as the situation became critical, some rally enthusiasts came by. Thanks to their winches and experience, they were able to help free the vehicle.

The second truck didn't have an easy ride either. As a result of heavy steering with low tyre pressure, a tyre got detached from the rim. With a steady hand and precise teamwork, the off-road crew stabilised the car in an inclined position, cleaned the rim and safely refitted the tyre.

The desert teaches you what really matters.

The Sahara is a tough place to be: although it took a lot of time and nerves of steel for the group to overcome the challenges that were thrown at them, they relished the desert's unique atmosphere. The evenings spent by the campfire, surrounded by nothing but sand and wilderness, remain as unforgettable as the challenges they conquered.

After three weeks and exactly 5,593 km, the group was able to look back on a truly fantastic experience. "The desert is more than just a challenge. It shows you what really matters", says Marie Trappen. What she means by this is obvious: reliable vehicles, good friends and the confidence to be able to count on the help of the Daimler Truck Community no matter where you are in the world.