Going down the rabbit hole...Fuso build


Preface: We are USA based and plan on mostly exploring North America. We are not new to adventure or traveling.

Well.. it's happened.. I'm down the rabbit hole of building a Fuso (or similar).
I'm capable of building things, maintaining things and general mechanics.

My wife and I have outgrown our space in our Alaskan Camper and are considering a new build. We currently run around in a short wheel base 2006 Quad Ram truck. With an 8' Alaskan Camper on a custom flat bed. We love it, but are ready for more. :oops:

While we enjoy our space in the cabin of our truck while we motor down the highway, we are considering exchanging that for a larger living space. COE vs Long nose.

I'm working on the thought process of the truck at this point in the design process. We've also started a thought track around the interior design, and requirements as well. Understanding that they are related, but mostly mutually exclusive of each other. We do believe we'd like a passthrough (for convenience and possible medium sized four legged traveling companion)

On the truck part.
1. How interchangeable are the parts between models? generations? If I have a chance to by a rusted out 2001 FG140 with 4x4, could I easily move the front (4wd components) to a cleaner/newer truck? what about between different models and years?
2. reliability is important to me. i like well maintained equipment. Am I asking for trouble down this rabbit hole? (note: i currently own 3 land rovers.. soooo..)
3. lets talk cab comfort. I understand they are city trucks. but how do they fair for 5-10 hrs in the seat across the southwest? i fully plan on swapping seats to something built for the long haul. I have scheel-mann now.. I like them, but open to options. I plan on doing sound treatment.
4. Suspension. Is this going to be a one off experiment, or are there some tried and true methods that just seem to work?

Thanks and looking forward to the discussions.


Crazy Person
If you do a bit of searching in this forum you will find answers to pretty much all of your questions, as they have been asked and answered previously.
Be mindful that the 4x4 Fuso has a stepped chassis, to allow for clearance of the front diff. All of the 4x2 models have a straight chassis, so this is definitely not an interchangeable part. The chassis is normally where you would find the most/worst rust, so that may be an issue. There are a few members here that have had a new chassis manufactured, but I don't think that this is a cheap exercise.
I will also add that the OEM suspension is only good for 2 things... loosening your fillings and unwanted spinal adjustments. The front leafs are short and stiff, which for a COE vehicle is definitely not ideal. To use one of these trucks as a expedition camper, this is an area that needs a lot of attention. I have a 5 link coil suspension conversion on my 2010 Fuso, but still, it's a truck and will always ride like one.
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New member
So I did the same thing, bought a rusted 2000 FG639 to rebuild just about a year ago. There are a ton of parts interchangeable between 1996 - 2004, encompassing the FE/FG 639/649 and some other variants like the FE640. I know this because this has been the source of parts for my project. I’m not familiar as much with trucks beyond 2004 since it was a significant change after that year.

SkiFreak is correct in that the FGs have a stepped frame, different from the straight frames you find on the FEs.

However, you can still pull a frame from an FE and use for an FG. They literally took an FE frame, cut it at the front 1/3rd, and attached a step piece, then rejoined the frames.

It’s how I swapped the front frame on my FG using a frame from an FE. Thankfully the joiner that allows the step on my FG was in good condition, otherwise I really would have been out of luck.

It’s also a complete PITA to do, but hey, I did it on my driveway with no garage, just takes perseverance.

As for suspension people swear by Alcan Springs in Colorado, so I’ve heard.

Good luck with your build!


Active member
I changed my mind and went with a Isuzu. You can do something decent for $60K

Some other guys pic


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Wow! Everything I could have hoped for with the responses... Thank you all.

I appreciate the details. A lot to keep thinking about. Keeping my eye on the prize, the habitat :)


10 years ago I considered the same switch until I drove a 4x4 Fuso and decided that for North America with so much highway driving that I'd stick with a full size diesel pickup. "It's pudding time!"


Can we talk low range transfer case for a minute?

I'm coming from a Ram 2500 4x4 (when loaded about 10k pounds) and a Land Rover Discovery where low range is used quite often. Bouncing around Canyonlands, muscling up and over Ophir pass in Colorado. etc.

I understand the NA 2014s don't have a low range, and from what i'm reading, there isn't a good option to add one.

Is the gearing in a 2014 such that 1st gear would allow me to explore the places I love without the low range? Is High Range and 1st gear sufficient?

Should I be considering a older model truck with low range? I use low range in my stock geared Ram to give that extra power to get up off highway access and forest roads quite often.


Desert Dog

Regarding low range - if you really want to get the most out of your Fuso, you will definitely need low range. Just recently I did a extremely twisty mountain pass where I was in low 2nd all the way up as well as down.


Thanks @Desert Dog , that is my hunch as well. I was thinking 4wd without low range would limit where I could go.

I did find a 2003 transfer case with low range. in the US.

Is my research correct in that the 2003 transfer case could be swapped into up to 2007 year model truck?
What’s the 1st gear ratio in the Duonic? And axle ratio and proposed tire size.
As a very general approximate rule, you want at least 40:1 (trans x TC x diff) in lowest gear, for a “light” vehicle with ~32” tires.
Lower is better especially for heavily loaded or bigger vehicles - like camping rigs.
Someone in Australia built a 6x6 Oka with this transmission:
It has a 2 speed TC as well.
So what’s the Duonic’s gear ratios?
What’s the 1st gear ratio in the Duonic? And axle ratio and proposed tire size.
As a very general approximate rule, you want at least 40:1 (trans x TC x diff) in lowest gear, for a “light” vehicle with ~32” tires.
Lower is better especially for heavily loaded or bigger vehicles - like camping rigs.
Someone in Australia built a 6x6 Oka with this transmission:
It has a 2 speed TC as well.
So what’s the Duonic’s gear ratios
Looked up in a Haven 2013-14 post:
Manual trans, 2 speed TC = 54:1
Duonic, OPTIONAL lower axle ratio, 31:1
About 29:1 with faster axle ratio


Yikes.. thanks Charlie.
The differences are significant.. and make me pause on the Duonic.
i guess I need to short list down to pre-2005 models to get the low range.
Reading some other threads, this might be the better (and more serviceable) option anyway.
Start with a lower cost pre-2005 model. gut it, clean it, do suspension, seats, swap in xfer case with low range (if needed).


Kodiak Buckaroo
With the Duonic transmission it is not just the gear ratios, but the computer 'brains' running it. Hopefully @Czechsix (2014 FG) will 'czech' in here, but if I recall correctly, he could not pull up and press his front tires against a curb, and then drive over it, as the computer thought something was wrong. A moving start would surmount the curb, but not from a standstill.
Disclaimer - internal memory storage is degrading :rolleyes:

2007 and before for the 'normal' transmission and 2 speed transfer case.

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