If you love living in RVs that can take you literally anywhere, then you are going to love this Ford F-450 Xplorer Xcursion RV, 6.7L Cummins I-6
WHILE HORSEPOWER and torque typically head the list of qualities, capabilities, and other criteria that come to mind when we think about diesel engines, another more important word, “freedom,” seldom does.
Carl Montoya’s ’04 Ford F-450 Xplorer Xcursion RV is a running, driving, Cummins-powered freedom machine that carries him over territory few motorhomes would ever be able to navigate— to places some folks will never have the pleasure of experiencing. The rig does so thanks to an engine swap and some crafty upgrades that take this machine from mildly capable to virtually unstoppable. There aren’t many trucks Diesel Power has featured designed to do what this one does, and that’s what makes it so interesting.
To understand this truck, we first need to understand its owner. Carl Montoya is the proprietor of Nitro Gear and Axle and a lifelong lover of the outdoors. When it was time to look for a vehicle that would be good for his business and his lifestyle, the idea of a four-wheel-drive motorhome was perfect for him. Carl wasn’t looking to go rockcrawling, but he wanted something that would handle mild off-road situations and take him to the places where living “off the grid” was truly off the grid. “When I first found this rig, I was looking for a four-wheel-drive diesel RV,” Carl says. “Most of the motorhomes out there have gas engines and are built with lighter-duty chassis than this F-450–based truck. They are limited in their towing capacity because of their weight, and they can’t support the things I want to do.”
Things were looking up when Carl located this Xplorer Xcursion in Montana with only 19,000 miles on its odometer. “The RV had a 6.0L Power Stroke engine that was having the common head-gasket issues those engines have,” Carl explains. “I got the truck for a good price and had the engine gone through with all the typical fixes, like head studs and other upgrades. My plan was to leave that engine in the RV for the long haul.”
That plan didn’t come to fruition, unfortunately, and Carl made a very significant change out of sheer frustration. “The 6.0L Power Stroke engine was a constant source of problems for me. Every time I would go somewhere, I was having these random little issues. Sensors and other components were failing,” Carl says. “Finally, we were on the way to an event in Moab (Utah), and it was blowing coolant out of the exhaust whenever we climbed steep grades. The truck only had 43,000 miles on it, and I knew I needed to do something.”
After the event, Carl reached out to Diesel Conversion Specialists in Montana. The timing was perfect, because they told him to bring them the rig and they’d get on it immediately. After gingerly driving the truck to the shop, Carl discussed the build with the team at DCS, and they decided to use a 6.7L Cummins diesel engine for the RV. “The 6.7L was a little more challenging for the DCS team to work with, but they learned some things along the way, and it was the right move,” Carl says.
YEAR/MAKE/MODEL: ’04 Ford F-450 Xplorer Xcursion RV
OWNER: Carl Montoya
HOMETOWN: Wenatchee, Washington
ODOMETER: 57,000 miles
FUEL ECONOMY: 13.8 mpg highway/10 to 12 mpg towing
ENGINE: 6.7L Cummins I-6 ARP head studs
FUEL: Fuelab lift pump, FASS Diesel Fuel Systems in-tank pump, stock injection pump and injectors, SCT and EFILive tuning, three 20-gallon fuel tanks
AIR: AFE Power cold-air intake, K&N Engineering air filter, 62mm Diesel Power Source turbocharger over a BorgWarner S475, Banks Power intercooler, High Performance Silicone boots and clamps
EXHAUST: Diesel Power Source manifold, Diesel Conversion Specialists downpipe, MBRP tube
TRANSMISSION: 5R110 five-speed automatic by ATS Diesel Performance, Five Star torque converter, stock controller with Diesel Conversion Specialists tuning
FLUIDS: Lucas gear oil, Ford ATF
HORSEPOWER: 600 hp
TORQUE: 1,200 lb-ft
TIRES: 335/80R20 Goodyear G275 MSA
WHEELS: 20×11 Buckstop reversible
SUSPENSION: ’05-and-up Ford F-550 coil spring, leveling spacers (front), 12,000-pound leaf springs (rear), Firestone airbags, Radflo Suspension Technology custom-valved 2.5-inch shocks, Hellwig Products sway bars
AXLES: Dana 60 “Fatboy” with Nitro Gear and Axle 5.38 gears, Eaton ELocker differential, Nitro Xtreme differential cover, Spicer 35-spline inner/outer shafts, Warn locking hubs, Performance Steering Components 10-inch-travel hydraulic-assist steering ram, 1550 series Spicer universal joints (front), Dana S110 dropout-style axle, Nitro Gear and Axle 5.38 gears, Detroit Trutrac limited-slip differential (rear)
BODY: Xplorer Xcursion RV, ASFIR 4×4 winch bumper, Factor 55 ProLink, Rigid LED lightbar and foglights, ’07 Ford Super Duty grille, headlights, and mirrors
INTERIOR: Edge Products instruments, accommodations for six, full bathroom, 100-gallon freshwater capacity, air conditioning, 5,000-watt generator, LCD television, Bluetooth stereo, cooktop, Norcold refrigerator
FUN FACT: The exterior Nitro Gear and Axle wrap on the truck features Bomber Cliffs, a Mission Ridge, Washington, ski area.
“The extra displacement and the Diesel Power Source compound turbochargers, along with the other upgrades, really make the engine a stout piece. With the truck’s gearing and other upgrades, the Ford engine was not lacking power, but I just could not deal with the reliability problems.”
When Carl got his RV back a month later, it was love at first fire-up. “The Power Stroke needed to be revved to make power, and the transmission was shifting all the time,” Carl remembers. “This Cummins likes to lug along, and it delivers incredible fuel mileage. I have seen 13.8 mpg when not towing and an average of 10 to 11 mpg when towing a trailer. The hilarious thing is that I get about 10 mpg when I drive my Land Cruiser by itself. When a vehicle with a weight rating of about 26,000 pounds is getting the same mileage, that’s pretty awesome.”
The engine isn’t the only nontraditional piece of F-450 hardware that supports Carl’s motorhome. “Until 2004, the F-450 used the same front axle as the F-250 and F-350. However, in 2005, Ford went with an axle that is coil sprung and 6 inches wider,” Carl explains. “The axle is bigger and beefier in many respects, but it was also redesigned to give more steering angle. The RV now has a tighter turning radius than many pickup trucks because of the axle swap. We added a 2-inch leveling spacer to the front end when we did the swap. The rear has 12,000-pound springs and a custom-machined lift block.” The wheels are reversible Buckstop 20-inch wheels, mounted on 41-inch-tall Goodyear G275 MSA military pieces. With the axle, it’s a package that solved a ride-quality problem that needed to be remedied.
“There aren’t many trucks Diesel Power has featured designed to do what this one does, and that’s what makes it so interesting.”
By now, you have figured out Carl isn’t the type of guy who likes to pull into the local campground and simply plug in his RV. “This is a very versatile truck, and I have lived in it for months at a time,” Carl tells us. “It is designed to be self-supporting. It carries 100 gallons of fresh water, it can sleep six people, and the only real challenge that crops up is keeping things from freezing when it is subzero outside.” While the truck gets plenty of use at industry events and gatherings, it isn’t just the diesel fans or hard-core gearheads who enjoy it. “The crazy thing about this RV is that everyone loves it,” Carl says with a laugh. “Grandmothers, kids, and even people who would probably not be considered diesel enthusiasts like it. Most people dig it for the off-the-grid persona the truck exudes.”
One thing Carl isn’t trying to do is make a habit of hitting hard-core trails. “You do have some of the RV element to deal with: drawers and cabinets that can open up on side angles. There’s also the fact that this is a long and tall vehicle with lots of overhang,” Carl explains. “I followed a Jeep Rubicon on a trail that was probably more hard-core than I expected it to be. Lifting a wheel in a vehicle that weighs 17,000 pounds is cool, but you don’t want to do it a lot because it can be punishing on the chassis with all that weight. The rear overhang can be a problem in big trail dips and coming off of rocks as well.”
If you live in the Pacific Northwest and you happen to see the coolest F-450–based RV you’ve ever laid eyes on rolling down the highway and you are not driving a four-wheel drive, don’t follow Carl Montoya. Once the pavement turns to dirt, this diesel rig shines, and you’ll be left wondering where the big beast went. Diesel performance is one thing, and diesel freedom is another. Thanks to thoroughly researched modifications and a complete repower, this rig has high levels of both.
This is exactly what Carl Montoya envisioned when upgrading his ’04 Ford F-450–based RV. It’s a capable off-road machine that’s powerful enough to tow his trail rigs and fit enough gear to support him living completely off the grid whenever he wants. | Diesel Conversion Specialists performed the engine swap. The troublesome 6.0L Ford Power Stroke was ditched in favor of a rock-solid 6.7L Cummins. The truck uses an ATS Diesel Performance 5R110 five-speed automatic transmission with a reprogrammed Ford controller. | Diesel Conversion Specialists did its normal ultra-sanitary job on this swap. The 6.7L Cummins looks like it should be a factory option in this Ford. Carl is extremely happy with the truck’s increased power and better driving manners. | Navigating the trails in a rig this big and long can be tricky. But, with forethought and good driving, Carl manages to keep trail rash to a minimum. He also has to be careful not to launch the groceries out of the cabinets! | The axle swap also created a change from leaf to coil springs in the front. Here we can see the beefy ASFIR 4×4 skidplate and the Performance Steering Components hydraulic ram in the steering system and the Nitro Gear and Axle beefy differential cover. | With a 600-mile fuel range, 100 gallons of fresh water on board, and all the comforts of home, Carl has actually lived in this rig for months at a time. He’s in it almost every weekend, adventuring or attending events and shows for Nitro Gear and Axle. | The Bushwacker fender flares are in place because of the truck’s front-axle swap. By using an ’05 Dana 60, the track width is increased by 6 inches. Ironically, the turning distance is shorter due to the axle’s more modern design. | This photo clearly illustrates the increased width of the Dana 60 axle. Other than the Cummins swap, this is Carl’s favorite modification. | Here’s the spot Carl loves to be: the driver seat of his rig.
This F-450–based motorhome is truly a diesel-powered room with a view.