Kenworth K370 6X6 with BoxManufaktur Habitat & Torsion Free Subframe

DeAusten

Member
OK, here we go:

In May of 2020 I purchased a 2019 Kenworth K370. The vehicle was new but had been sitting on the lot for some time, and meant that I could avoid a lengthy lead-time wait, and a pretty significant premium for purchasing a vehicle new from the factory. I've always been a fan of cab-over style trucks, and knew that I wanted a cab-over for my chassis which really helped narrow the options. Prior to purchasing, I took a long look at the offerings from Acela, some of the 25 year old+ options available in Europe, and the K370 (I would have purchased a newer MAN chassis without question, but they unfortunately cannot be imported back here to the US). Ultimately I picked the K370 based on price, and serviceability. The K370 has some major downsides, but nothing I felt I couldn't ultimately address during the initial build, or at a later date.

Immediately after purchasing the chassis, I had the truck shipped to Ronnie and Todd turner at Tulsa Truck Mfg. It took some convincing, a few dozen emails, phone calls, and a visit but we ultimately landed on a plan to convert the stock 4x2 K370 into a 6x6. During the conversion the guys at Tulsa Truck removed the front and rear axles, replaced them with new Meritor axles, full lockers, air bags all around, and replaced the stock tires with a set of Goodyear G278 445/65R22.5 wheels. I can't say enough about my experience working with Tulsa Truck Mfg. I worked with Todd primarily throughout the process and learned a great deal in the process. The guys at Tulsa Truck perform a service that not many others in the US are willing to do, and they're incredibly professional and fun to work with.

At the same time the 6x6 conversion was taking place, I began working with BoxManufaktur on plans to build a habitat for the back of the truck. Similar to my process for selecting the chassis, I spent quite a bit of time researching turn-key builders from Unicat, Krug, BoxManufaktur, and Bliss Mobil, and Global Expedition Vehicles. Ultimately I picked BoxManufaktur after a few lengthy calls with the founder, Andreas. What really sold me was his friendliness, and willingness to collaborate and customize the box design. If you haven't seen their Instagram, take a look at @boxmanufaktur and you'll get a real sense of just how far you can customize one of their boxes. One of the major downsides to BoxManufaktur is their lead time, however in my case.. that was not an issue as my truck was still under construction. The box I ended up designing is 24.5ft long, with a 45 degree taper at the end, a large garage, drop down entrance, hydronic heating in the floor, and a cab-to-cabin access. The box will be empty when I receive it, and I will complete the interior build out myself. BoxManufaktur has been highly responsive, and working with them over this past year has been incredible and a true learning experience.

I decided to go with Outbound windows. It was a difficult decision based on their price, but ultimately the selling point for me was their durability. I have seen a number of builds that use dual pane acrylic windows that offer similar thermal properties to dual pane glass windows for a fraction of the cost but are somewhat susceptible to scratches from trees. Windows and natural light are incredibly important to me (you'll see shortly) and so durability was top of mind, and windows were something I wanted to get right the first time as I have quite a few.

The subframe: not unlike toilets on this forum, subframes also seem to get people riled up. After much research, and calling around.. I ended up speaking with Quade from Overland Adventure Truck. Quade is a wealth of knowledge when it comes to vehicle subframes and mounting systems, and through talking with him we ultimately landed on a design for a mounting system to sit between the frame rails of the truck, and the BoxManufaktur habitat. The design was informed by the flexion in the truck frame rails while weighted down. Ultimately because the truck chassis is somewhat long at 30', it ended up flexing quite a bit more than expected, and thus a 4-point torsion free subframe was selected to give the truck frame ample room to flex underneath. The box has not been mounted to the subframe yet, but in my testing I have been nothing but impressed with the engineering and results. My experience working with Quade has been nothing but positive, and after the box is mounted to the subframe, the truck will return to Overland Adventure Truck for a few more upgrades including a hydraulic lift.

Where we are today: Last week I drove the truck down from Seattle to the port in Galveston TX. Due to COVID and the impact it's had on shipping, the price to ship the box from BoxManufaktur via container ship became unrealistic. It became cheaper to ship the truck to BoxManufaktur for mounting and upgrades via Roll-on Roll-off (RoRo). I expect the truck to ship out within the next 3 weeks, and arrive to Germany in mid to late October.

Still to come, once BoxManufaktur takes possession of the truck once it's in Germany, they will handle working with a vendor to extend the cabin of the K370 to a sleeper (the K370 is just a DAF LF, and you cannot purchase a K370 in a sleeper configuration in the US but there is no shortage of sleeper DAF LF's in Germany), mount the box, complete the cab-to-cabin pass through, and apply a paint job. Once that is complete, the truck will be loaded back onto a ship and return to the US.

I've attached a number of designs of the truck, as well as some photos throughout it's build process. I am not expert in CAD, but have taught myself enough to create a to-scale model of the truck which I have been working off of since the beginning of this project. I'm always open to honest feedback, and will keep this thread up to date as the build progresses! If you're interested in seeing more, I have posted and do post quite a bit of build progress on my instagram @austendewolf

As for my motivation, I'm definitely a project person and I've always loved the idea of these adventure vehicles. I thought now would be as good a time as any to apply my mind to something challenging. I previously spent a year touring and living in a van and really enjoyed the flexibility it offered. I'm hopeful that I'm able to build this vehicle into something that allows me to do similar, for longer.

Austen
 

Attachments

waveslider

Outdoorsman
Nice to see someone who shares our desire for windows and natural light. Bravo. I can also say that the folks at Tulsa Truck have helped anytime we've needed it which hasn't been often but definitely critical when we did.

If, during your interaction with the folks in Germany you encounter a good parts supplier for the DAF trucks - that's willing to ship to the the US - please don't hesitate to share. There are a multitude of small bits and parts that some of us KW owners would love to ship back here for installation.

Thanks for sharing.
 

bgrattan

New member
Wow. That picture taken earlier this month, where it looks like they (Tulsa?) are showing you the bed features, is impressive (photo name: 20210807_101042.jpg).
I hope you get another picture--after everything is put together--with the same amount of torsion on the vehicle. It'll be very interesting.
 

DeAusten

Member
Awesome truck! How long was the process at Tulsa? Did they stay on the timeframe they initially stated?
The truck was at Tulsa Truck around 6 months in total, however it wasn't being actively worked on until perhaps the last 6 weeks of that time period. They stuck to their time estimate, and the work seemed to go quick once it started. I let them know early on I was in no rush as the box was going to take much longer to build. I understand that their typical turnaround can be much faster than 6 months.
 

DeAusten

Member
Wow. That picture taken earlier this month, where it looks like they (Tulsa?) are showing you the bed features, is impressive (photo name: 20210807_101042.jpg).
I hope you get another picture--after everything is put together--with the same amount of torsion on the vehicle. It'll be very interesting.
Ah, that's the truck at Overland Adventure Truck, and the people in the photo are Quade (left), and myself (right). He's showing me the extreme degree that the truck flexes and if you could see my face it basically says it all as I thought the truck would be much more rigid. I'll be sure to snag another photo once it's back in the states put together. I'm abs curious how the subframe behaves with the box on board.
 

DeAusten

Member
Nice to see someone who shares our desire for windows and natural light. Bravo. I can also say that the folks at Tulsa Truck have helped anytime we've needed it which hasn't been often but definitely critical when we did.

If, during your interaction with the folks in Germany you encounter a good parts supplier for the DAF trucks - that's willing to ship to the the US - please don't hesitate to share. There are a multitude of small bits and parts that some of us KW owners would love to ship back here for installation.

Thanks for sharing.
Thanks waveslider. I don't know if you recall but we spoke about a year ago about the pros and cons of your rig, and ultimately it helped me decide to go in a similar direction. Anyways, your input is always appreciated.

Regarding the supplier, I worked with Vos Truckparts out of The Netherlands. I've found that many suppliers will not ship to the United States, but Vos Truckparts did not have an issue with it. They were able to deliver a quote to me for an entire truck cabin shipped to the US with insurance fairly quickly. Their website is also fairly navigable as well when it comes to parts. Curious if they might have what you're looking for.
 

shortbus4x4

Expedition Leader
Very nice build. I work for an International dealer and Tulsa Truck does our 4x4 and 6x6 conversions too, they do very nice work.
 

waveslider

Outdoorsman
Oh yes of course! I had forgotten. I'm glad you found it helpful - my opinion is worth every penny you paid for it! :)

Very excited to see it come together. Thanks for sharing and please keep us updated.
 

DeAusten

Member
Even a front locker? If so, which model Meritor front axle? And just out of curiosity, which model TC?
Correct, front locker as well. The front axle is a Meritor MX-17. I'm not sure what the transfer case is bolted up, I'll take a look next time I'm under the truck.

What is the engine, transmission, horsepower, torque?
The engine is a Paccar PX-7, 265HP, 660ft lbs of torque. The transmission is an Allison 2500 RDS. The engine in it's current form is one of those negatives I spoke about before. I think it's something I'd like to build up a bit in the future, but is fairly low on my list of things to do.
 

chris_the_wrench

Fixer & Builder of Things
Correct, front locker as well. The front axle is a Meritor MX-17. I'm not sure what the transfer case is bolted up, I'll take a look next time I'm under the truck.
I can't speak for your exact truck, but when I inquired with Tulsa about converting a k270 to 4x4, they were spec'ing it with a Marmon Herrington MVG-750 two speed transfer case. Ultimately I think that will be too big of a truck for our needs, but I'm really liking what your putting together @DeAusten !!

-Chris
 

Forum statistics

Threads
179,189
Messages
2,793,108
Members
214,174
Latest member
Sprock
Top