Unimog Expedition Camper Offers Comfort and Off-Road Prowess

Have you even seen an imported truck or vehicle that made you green with envy? For the Truck Camper Adventure team, the German-made Unimog is one such truck. When it comes to off-road prowess, there are few trucks more capable than the Unimog. The Unimog is a multi-purpose, automatic, 4WD, medium truck manufactured by Mercedes-Benz. Due to its high clearance and off-road capabilities, it’s a popular choice in the military, agricultural, construction, and firefighting communities as well as in the forest ranger and overland expedition communities. The Unimog also excels in snow removal and as a heavy-duty equipment carrier.

Unfortunately, the Unimog is rare sight in the United States. This is due primarily to the stringent vehicle regulations and emission requirements here for diesels. Most of the Unimog models in the U.S. are either older models from the 70s or those that have been recently imported by dealerships and by overland enthusiasts. Indeed, Freightliner, a Daimler-Chrysler subsidiary, tried to penetrate the North American market in 2002 with the U500 series, but after five years the company was able to sell only 184 units. Daimler-Chrysler claimed that the reason for pulling out of the North American market was the U.S. government’s new and more stringent emission requirements, but poor sales had to be a significant factor as well.

One particular Unimog build that caught our eye is a rig owned by Dirk and Sybille Feldmann. The couple purchased their Unimog—a 1992 437 U1350L—from a German fire department in 2018. As built, the 4WD truck came with a GVWR of 17,600 pounds and a payload of 6,600 pounds. This Unimog is equipped with front and rear lockers, a wheelbase of 151.7 inches, a 42 gallon diesel fuel tank, a 24 volt 55 amp alternator, an engine brake, and Michelin XZL 365/80 R20s all-terrain tires. The truck is powered by an OM352 Mercedes 5.7L I6 cylinder diesel coupled to a manual eight-speed transmission (the transmission also has eight reverse gears), and a 5:31 rear axle. Topping it all off is a camper built by two German manufacturers, one that built the box, the other than built-out the interior. To learn more about their inspirational build, we spoke with Dirk.

Thanks for talking with us, Dirk. Tell us a little about yourself? Where are you from?

Dirk Feldmann: My wife and I are originally from Germany, but have been living and working in the United States since 2004. First in Alabama, then in Pennsylvania. I was an executive for a medical technology company until I retired in February 2023 and my wife, who is a product manager for the same company, retired in March 2023.

Some time in 2017, we decided that we would retire at 52 to be, among other things, healthy and agile enough to travel the world in an overland vehicle like the Unimog. We crunched the numbers, accelerated our saving and investment plans and have been fortunate to be able to pull through with our goal.

Dirk and Sybille

Can you tell us about the Unimog and the camper?

Dirk Feldmann: The Unimog is a 1992 Unimog 437 U1305L. It started out as a fire truck in Germany and I bought it at a surplus auction directly from the township. It was in great condition with only 10,000 miles.

While we did the conversion of our Mercedes/Puch GWagon ourselves, we left this one to professionals. I flew to Germany to pick it up from the fire department and from each of the stages, which was super exiting. We had three different companies perform the conversion to an overland truck according the our specifications. Hellgeth, a Unimog specialist, did all the mods on/around the chassis. Boxmanufaktur built the habitat box in the back. JOKO Wohnmobil built the camper build as well as added some finishing touches to the rig.

Their Unimog as it originally appeared.
After the conversion for overlanding.
With the camper.

Can you tell us more the features and modifications of your custom Unimog rig?

Dirk Feldmann: As a custom overland truck, our Unimog is full of features and modifications. Here are some of most important:

Truck:

  • Added an overdrive and larger tires for lower rpm’s at speed/higher top speed.
  • Extra low subframe for camper box to lower total height
  • Hella LED headlights, XXX LED off-road lights and surround lights
  • Custom aluminum roof rack (80 pounds weight) with spare tire and removable crane
  • Hellgeth developed air conditioner
  • Air dampened, heated seats with integrated seatbelts
  • Additional sound proofing of cab
  • Cutout for walkthrough to the back
  • Special material between cab and box to flex with the chassis. Same material that is used between cars of the German high speed trains.
  • Additional deadbolts in the cab doors
  • Additional diesel tank for a total fuel capacity of 120 gallons
  • Additional heated SEPAR diesel filter
  • Diesel-powered engine heater
  • Pneumatically operated, heated grey tank maintaining the rear departure angle
  • Repaint in Agathe grey RAL color

Camper:

  • Light weight box with cut out wheel arches (due to the low subframe) and angled rear to maintain 45 degree departure angle
  • Five Dometic-Seitz windows and two marine-grade skylights
  • Reinforced rear wall for bike rack and airline rails
  • Light weight furniture build with U-shaped seating area, retractable bed, full kitchen and bathroom with shower
  • Retractable Unimog specific bike rack
  • Custom stainless steel lower storage boxes with a propane quick connect
  • Outdoor shower outlet
U-shaped dinette.
Kitchen
Wet-bath with Dometic Cassette Toilet.

Can you tell us more about your camper layout and features?

Dirk Feldmann: The full-size bed raises and lowers over the dinette manually. Storage is plentiful with overhead cabinets throughout. The plumbing consists of a 40 gallon fresh water holding tank, a heated 20 gallon grey water holding tank, and a 5 gallon Dometic cassette toilet with an SOG system, that eliminates odors by using a outdoor flapper to automatically opens and closes when you flush. Heating is provided by a Webasto Diesel-Air with a high elevation kit capable of operating up to 16,600 foot elevation. The refrigerator is a Kissmann 92L DC compressor refrigerator. We have two stoves for cooking. Inside we have a two-burner marine propane stove with baking oven and a two-burner propane stove with quick connect outside.

Your rig looks great. What do you like best about your setup?

Dirk Feldmann: We love our Unimog. The Unimog is an icon in Germany and Europe. We obviously like the way it looks and what it’s capable of. On the camper side, we love the bed, which we can lower from the ceiling in seconds and don’t have to “build” every night. Since it is retractable, it doesn’t take up much space when not in use. The other most loved feature is our quick connect propane outlet, letting us use our two burner outdoor stove in a snap. It’s a small item with a huge practical benefit.

Can you tell us about your camper’s electrical system?

Dirk Feldmann: The DC system consists of three 100 amp hour lithium batteries mounted in a box underneath the floor. Everything is electric, except the stove/backing oven and the heat, which is diesel-air with a high altitude kit for altitudes up to 16,600 feet. The system is protected by several fuse boxes and two F/I safety trip switches. The AC side can take both 110 volts as well as 220 volts shore power. We also have a 1,000 watt, 220 volt inverter.

How do you keep your camper batteries topped off?

Dirk Feldmann: Solar power for us. The system consists of four marine-grade roof panels totaling 440 watts.

Being a Unimog we suppose that you are under your truck’s GVWR? Have you had your rig weighed?

Dirk Feldmann: The Unimog was rated at 17,600 pounds as a firetruck. Once the Unimog rig built, we had it weighed and came in at 13,200 pounds wet, which we were very pleased with. We haven’t weighed the Unimog with our clothes and gear yet.

Did you need to make any modifications to your truck’s suspension?

Dirk Feldmann: The only modification we made to the Unimog were Koni shocks, which were developed by Hellgeth specifically for Overland Unimogs.

What other mods (if any) did you make to your truck?

Dirk Feldmann: Added a hard case for a little extra storage in the back as well as a rack for the Starlink dish in one of the storage compartments

Do you have any regrets in any of your truck and camper choices? Anything you wished that you had done differently?

Dirk Feldmann: No regrets really. The biggest additional mod we could have done is a on the fly tire pressure inflation system, but this would have required completely different axles from the German army truck “Dingo.” We skipped it, since we weren’t sure if the expense would bring us a benefit that would justify that type of an investment. Otherwise, if we would need to build another one, we’d pretty much build it the same way again, short of an additional 12 volt outlet and a slightly larger inverter.

What is your favorite truck camper mod or piece of gear that you take with you?

Dirk Feldmann: We really like our Helinox Sunset chairs that are light, (relatively) small and very comfortable. We are making use of our newest purchase, an inflatable kayak from Sea-Eagle a lot.

Homebase in Pennsylvania

What is the longest amount of time that you have spent in your camper?

Dirk Feldmann: About five months. In 2020, when our office closed due to COVID, we decided to leave Pennsylvania for warmer pastures in November. We locked the house up and didn’t come back until April. We spent this and the last winter in the South as well and have been traveling 13 months in the Unimog out of the last 2-1/2 years.

Where have you taken your rig so far?

Dirk Feldmann: So far, we have only been up and down the east coast during the winter, as well as West Virginia twice and upstate New York.

What kind of mileage are you getting with your setup?

Dirk Feldmann: My standard answer to that question is: don’t know, don’t care. I think I calculated it once last year and if I remember correctly, it was in the lower teens. I attribute this to the relatively low weight and the fact that we usually cruise around 65 mph on the highway.

What wheel and tires do you have on your truck and what inflation values do you typically run?

Dirk Feldmann: We have the heavy-duty version of the Unimog steel wheel: 11×20 Super. The tires are Michelin XZL 365/80 R20s. We typically run 36.3 psi (front) and 46.4 psi (rear). Off-road we air them down to 23.2.

What are your future plans? Where are you planning to take your rig?

Dirk Feldmann: This is where it will get exciting. We built the Unimog to be able to travel the world. This summer, we will be heading up to Nova Scotia and Newfoundland in Canada and will return at the end of the fall. Then it will be Western US, which will take us a while, followed by Alaska.We will be taking Central and South America next and, given that this is many years out, we haven’t decided if Africa or Asia will be next. As we retired young, we plan to take our time to travel and be in places, staying a little longer in one place if we feel like it and do volunteer work from time to time.

Do you have a website and/or social media channels that our readers can follow?

Dirk Feldmann: We have a YouTube channel with detailed room tours and walk throughs both of the Unimog and the Gwagon we built. Once we hit the road in the early summer, we should be uploading more videos frequently. We’re also on Instagram and can be found under @nofomog.

About Mello Mike 908 Articles
Mello Mike is an Arizona native, author, and the founder of Truck Camper Adventure. He's been RV'ing since 2002, is a certified RVIA Level 1 RV Technician, and has restored several Airstream travel trailers. A communications expert and licensed ham radio operator (KK7TCA), he retired from the U.S. Navy in 2004 as a CWO3 after 24 years, holds a BS degree, and now runs Truck Camper Adventure full-time. He also does some RV consulting, repairs, and inspections on the side. He currently rolls in a 4WD Ram 3500 outfitted with a SherpTek truck bed with a Bundutec Roadrunner mounted on top.

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