The Petersen's 4-Wheel & Off-Road Ultimate Adventure Is A grueling, weeklong, multi-state tour of the toughest 4x4 trails in the U.S., and each year, one vehicle is built to lead a pack of the most capable trucks in the country. This time, Technical Editor Fred Williams (and his army of builders), combined a brand-new '07 Jeep Wrangler (JK) Rubicon (4-door) with an '06 Dodge Ram Mega Cab diesel and put it on top of Power Wagon axles to create a Frankenstein monster that has never existed before: the '07 Jeep Rubicon 5.9L Cummins (a.k.a. Rubi Wagon). Here's how everything came together.
'06 Mega Cab Frame Swap
It didn't take long to realize that the best way to get a full-sized Cummins into the 1/4-ton Wrangler was to use a frame designed for the power and weight of the diesel engine. Luckily, an '06 Mega Cab on its way to the crusher was found, and everything except the cab and axles were used to build the Ultimate JK. The frame was longer than necessary, so a section was cut from the middle, and a 1/4-inch plate was used to strengthen the area and notched to accommodate the Jeep body. Then, the Wrangler tub was cut and channels were added that allow the frame kickups to enter the cabin so that the body can sit flat on the Ram frame rails. Custom leaf spring hangers and body mounts were added to the Dodge frame, and before the body was installed, it got a thick coat of Lizard Skin ceramic insulation.
5.9L Cummins Swap
The experts at American Expedition vehicles specialize in swapping 5.7L Hemi v-8 engines into Jeep Wranglers, but installing the long inline-six cylinder Cummins into the JK was a real challenge. Since the ISB would not fit under the JK hood and leave room for the custom Griffin radiator, intercooler, and Optima battery, the engine was moved back 12 inches, and new motor mounts were built out of 1/4-inch steel plates. This location would also keep the front axle and suspension happy along with the added bonus of giving the Jeep a good front/rear balance. Plenty of modifications were made to the firewall and footwells with a Hobart plasma cutter, but with HeatShield wrap on the hot engine parts and a firewall extension fabricated by AEM, everything fit behind the factory Wrangler dash. brothers Dave and Jordan Harriton fooled the Totally Integrated Power Module (TIPM) that runs nearly everything in the Wrangler so that it would play nice with the Cummins. Their work was a success, and the Ultimate Adventure Jeep never lit up the Check Engine light during its 2,000-mile trip across the USA.