My Cummins/Allison 1000 Freightliner MT45 Step Van Build


I'm watching. I test drove and very nearly bought a '76 GMC Value Van before I bought my wheelchair van. That particular one needed more work than I was able to do at the time though.


Greening Auto in Tennessee

Monster Beadlock/Raceline

Marsh Racing Technology (MRT)

Ag Wheel and Tire in Wichita

Vision Wheel

Alcoa Wheel

Hutchinson Wheel

Longs Wheel in Jacksonville

Rays Engineering/Volk (by special order for truck)

Custom Alloy Wheels: – made in CO/CA
Intro, Boze, Bonspeed, Billet Specialties, Budnik, Colorado Custom, Centerline, Weld, Pro wheels all made in USA. Check Forgeline, Fesler, Alcoa as well as Japanese/German options, hoops and centers.

OMF, Accuride, BBS and many others all make custom wheels or have wheels that can be adjusted such as stock wheel, but you choose bolt pattern and offset.

Run quickly from Stazworks and Rickson. A few weeks of reading material on almost any majour off road forum will explain.

Your choice but I wouldnt choose them for wheels on my truck.

Very cool platform and nice setup, looking forward to the build. :beer:

PS: receptionist/secretary types are pretty faces, sometimes in more ways than one. Don't trust them for accurate information, at least that has been my experience. They neither control nor influence work quality, customer promises, delivery dates, shipping and the like.
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New member
Freighliner MT45

Looking forward to some updates on this build. We have the same thing in mind minus 4wd. Looking at acquiring a used MT45 as well to convert to a travel vehicle and eventually into a motorhome.


I have been contemplating an Adventure RV rig for some time now as part of our retirement planning. Wanting worldwide travel capability, I have gone the complete conceptual gambit starting with considering converted military trucks, moving to Fuso based units, and then converting an existing RV to a Cummins 6bt/Allison 1000/Dana 4x4 drivetrain. The drivetrain idea came to me after stumbling onto the “Crawler Hauler” project on the Xtreme Off Road TV show when they converted an Isuzu cab over to haul a rock crawler buggy. is the link to the first show in the series. While there are many different cool RV platforms that would benefit from this swap, they all would require a lot of fitment problem resolution and time consuming work. Also this is my first 4x4 truck project so I'm learning as I go, and my knowledge base is limited.

Then I came across the Freightliner MT45 – Utilimaster Step Van option during my Cummins/Allison research. This is the ubiquitous Fed-Ex delivery van that comes in various lengths, rear door options and load capacities. Besides having the desired 6bt engine, A 1000 transmission, and all the plumbing including the intercooler in place, the beauty of this option is that the box van is the most efficient use of space and has standing headroom throughout. Having the big living room on wheels with everyone in the same space is important to us as we are hoping to have friends and family fly out to travel with us from time to time. Extra sleeping space will be provided with a free standing tent on the upper deck. Separate cab/camper rigs don’t have that higher passenger capacity we seek. A disadvantage is our rig won’t fit into a shipping container.

I just started the build process this September by finding a 2004 (pre-low sulfur diesel) Freightliner MT45 with only 50k miles on There were a lot out there with high mileage, but with patience I found the ideal unit; low miles, 14’box, and open out (vs. overhead) rear doors. Check the VIN with a Freightliner Dealer to be sure you are getting the A1000 Transmission before you buy if you want to go this route.

I also obtained front and rear 4.88 axles from donor leaf spring Ford Super Duty F550’s the day after Christmas. Home Run Auto is a recycler specializing in Ford Super Duty Trucks in Tea, SD just outside Sioux Falls. I found Brian very knowledgeable, and a joy to deal with. The front axle is the well-known Dana 60, and the rear is the lesser known Dana Spicer 135. The rear S135 is about as stout as they come for this application, but the parts are expensive; a ring and pinion is over $1,200.00 for this rear end.

I just ordered Continental MPT81 335/80R20’s on custom conversion single rear wheels from Rickson Wheel Manufacturing. Big wheel wells are another great feature of the Freightliner MT45. Also on the way are 5.38 gears, lockers front & rear, and master rebuild kits from Randy’s Ring and Pinion. The transfer case will be a GM NP-261XHD manual shift rebuilt by Midwest Transmissions. They will install an aftermarket slip yoke eliminator by Canada’s Northwest Fab along with an oil pump shield to protect the case. Right now I am thinking about keeping the rear springs as is with 13,000 GVW and adding Firestone air bags on all four corners. The total cost of the 4x4 conversion is approaching the cost of the base truck.

I am estimating a total project completion time of three years. The 4x4 conversion is planned to be completed by mid-summer this year. By summer 2016 the major body modifications should be complete. They include the upper deck (fiberglass dock planking?), replacing the sliding doors with fabricated automotive style hinged units with roll up windows, and relocating the rear doors w/frame to the right side so they open under the canopy for that “step out to the deck” effect. The rear door opening will be filled so the toilet and shower can be fitted all the way to the rear, and sliding bus windows added to the living area. The aluminum body makes these mods easier than they would be with steel; the panels are thick & flat, easy to cut, they either rivet or are easy to weld with a MIG spool gun with less distortion.

Another feature I’m hoping to pull off is a giant bench front seat with a back that will flip over making a sofa that will face the living area when parked. The old railroad coaches had these so passengers could face each other. If I could also make this “sofa” fold down into a bed, that would be slick. I’m hoping to sleep 4 adults in the main cabin. The final summer of 2017 will be installation of all the “Life Support Systems”. I’m going to leave the planning of this phase until later as new product developments are always being released.

Our retirement vision includes initially living without real estate, and having a 30’ trawler cruiser to add variety to the Overlander adventures. Having the extra Cummins power will be helpful in moving the boat from venue to venue. Our first destination will be the Baja with discovering the world's most beautiful and remote beaches a retirement objective.

The common thread of all the build threads here is patience in getting updates and answers to questions, and I am no exception. We have quite a bit going on getting ready for retirement, and the build is only a small part of what needs to be accomplished, but I’ll try my best to be timely to questions and comments. Thank you for your interest in this build

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Awesome project..and something I have in mind too,,plz keep us updated..
Just wondering if those springs arent bit too stiff and will make the ride awfuly hard,or do you plan on removing few leafs?


New member

When you do the math with all the added weight for camper water and waste should take GVW to the limit. I think the springs should be fine. I'm also planning to have helper air bags on each corner.


New member
UPDATE 11/27/2015

UPDATE 11-27-2015
Sorry for the long absence folks; the planned early fall update was interrupted by some health and personal complications. My recommendation is to start building your RV early; it’s a complicated process. Overall, my retirement plans are moving ahead; much progress was made on prepping to sell the house with a basement remodel. I also sold most of my motorcycles and I am pairing down possessions at every opportunity. I’m certainly motivated to start the great adventure! Also, I did go through the hassle of getting the Freightliner MT45 title changed to a Motor Home classification with the installation of a temporary bed and stove to meet the Michigan requirements. This is a big annual savings on plates and insurance.
Getting a new separate credit card is another tip for a project of this magnitude. I essentially got a 0% six month loan on all the 4x4 parts during the teaser rate period. That really helps out the cash flow. I also like the separate dedicated record of all the RV purchases.
This RV project has reminded me of the saying “I’d rather be lucky than good”. I now must be a beyond good fabricator because of a few unfortunate twists of fate. The rule of the six P’s is another of my favorites for this project; Prior Planning Prevents P*** Poor Performance. Perhaps more prior research on my part could have avoided these “challenges”.
First, the Allison 1000 transmission uses a different spline count on the output shafts for the RWD and the 4WD NP 261 versions. Now the transmission has to come down and apart to install the new $825.00 tail housing and output shaft. I would recommend a divorced transfer case if I were to start over again, but the rebuilt NP 261 has already been delivered. The thought that the engine and transmission would be staying in-place was a real plus when I chose this approach.
The biggest challenge so far involves the electronics. The Freightliner MT-45 on-board Controller Area Network (CAN) is expecting to see a true 4 hub ABS system. The Ford F550 donor 4X4 axles use a 3 channel ABS system with single sensor on the center rear differential. With the help of a local rapid prototyping firm, I’m now creating rear hub steel tone or exciter rings and installing magnetic sensors for the Ford Dana Spicer 135. The drum parking brake is being gutted to make room for the new ABS hardware, and a pinion emergency disc brake has to be fabricated as a result. I didn’t see this one coming at all; ouch, a lot of lost money and time.
Back in June, I did pick up my Rickson Wheels at the factory, and ultimately I am satisfied with my purchase. But, what a trip dealing with Dan Richter! Prior to purchase on the phone, I shared the negative Rickson feedback with him and held out the promise of favorable words here if all went well. At the end of the process, disconnected and aloof are best words I can use to describe communications with Dan. I had a bit of anxiety if the wheels would be ready on time, since I was picking them up at his shop on the way back from an east coast family visit. He got most of the facts of the transactions confused. He showed up two hours late, which is a big deal in the middle of a 1200 mile trip. Then the wheels were powder coated black instead of the silver as ordered. He offered to correct the order ship the goods free to Michigan, if I wanted. At that point, I just wanted out and did not want to prolong the agony of dealing with him. After I was on the road with the black wheels and tires in my pickup truck, I called Dan back and asked for a $500 refund on the purchase; the amount he would have paid for shipping the corrected order. To his credit and my surprise, Dan agreed to do that. The problem was he never initiated a credit refund with my credit card company and this got to be very annoying with multiple phone calls and e-mails. The problem was eventually solved by contacting my credit card company and filing a disputed charge claim.(a good point to remember) The card company credited my account with the $500 and gave Rickson 30 days to dispute my claim; they did not so the credit stands. So that’s the Rickson story; Dan’s a nice guy with a good product, he just should not be dealing with customers.
So, finally most of the parts are in, and the axles are starting to come apart for the rebuilding process. I’m planning on have the axles ready to be installed in the early next summer. Getting this baby into 4WD mode has become my obsession.
Thanks again for your interest in my project.

Rear Axle Sandblast.jpg

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Expedition Leader
Thanks for the update. We've missed you.

Good luck with all of the hassles that seem to come with being among the first to try out a perfectly sensible idea. ;)


I love these custom builds. Beware of the project iceberg. Only a portion of the engineering and budget can be seen above the surface.


I understand the tires will cause x amount of lift to fit but was really wondering how much lift a straight front axle is going to raise up the van.

This is somewhat determined by oil pan clearance I guess.

Did not know how much the stock solid axle is dropped for clearance from the factory and if measuring that rise on the ends for the spindles will be a rough idea or not.