Ultimate Adventure 2007 Jeep Wrangler JK - UAJKPosted in Project Vehicles on November 1, 2007 0) (
So where were we? In the last three issues of 4-Wheel & Off-Road we've been building up an '07 Jeep Wrangler JK for our annual Ultimate Adventure trip. U.A. is the week-long off-road trip we do every summer, and as usual we're building an over-the-top 4x4 to lead our group of 20 rigs. Now if you look elsewhere in this issue you'll see the completed Jeep running the trails in Texas, but due to the magic and mysteries of magazine edit, this is a behind-the-scenes of how we built the Jeep for the trip. To catch up any stragglers, we started with a two-wheel-drive, four-door Wrangler and took it to get a custom rollcage done at Twisted Customs, then we drove it to American Expedition Vehicles (AEV) where we began combining the channeled Jeep body with a shortened Dodge Mega Cab frame since our plan included a Cummins diesel engine to repower our Ultimate Jeep. It all sounds simple when written out like this, but in fact the crew at AEV spent more than 400 man hours cutting the Jeep body to fit over the frame and drivetrain, plus the engine was moved backward approximately 12 inches to fit under the hood better, not to mention all the messin' about with wiring, plumbing, and suspension to get it just right.
In addition to the Cummins engine, we installed an NV4500 five-speed manual transmission-because we feel Jeeps should have manual transmissions-and a two-speed Atlas Transfer case, both of which were supplied by Advance Adapters. Also this month we'll cover the installation of a set of AAM axles from the new Dodge Power Wagon. We chose these axles because they will bolt right into the Mega Cab suspension, plus they are fitted with selectable lockers front and rear and 4.56 gears which should work perfectly with our new 42-inch BFGoodrich tires. Yes, there are some new treads on the market and we happened to get our hands on the very first set of 42s from BFGoodrich. As you can see, this Jeep buildup is quickly getting out of hand and surpassing the basic build that most of you will ever attempt, but hey, you've got to admit it's pretty cool. Take your basic Jeep, add all the coolest parts Dodge and Jeep have to offer, and what do you get? A bit more than a Rubicon Wrangler and even a bit more than a Dodge Power Wagon, It's the UAJK, but we call it the Rubi Wagon.
The electrical portion of the build would have been a nightmare for sure if it wasn't for the expertise that AEV has with Jeep and Dodge vehicles. Brothers Dave and Jordan Harriton have been working on everything from making the newer Hemi V-8s run when transplanted into Jeep Wranglers to building modules so that the traction control in the Jeep Grand Cherokees and Commanders still works correctly when those vehicles are modified. The current electrical system in the Jeep Wrangler is referred to as a Can Bus network system where there are numerous computers talking to each other and sending electrical messages over the wiring harness thousands of times per second. Included in this system is a primary computerized fuse block known as the Totally Integrated Power Module (TIPM), which helps monitor and disperse power to all the different modules and engine components throughout the Jeep. However, along with this communication from each component where things like the radio, stability control, ABS, and powertrain control module report back their own performance, there are also messages between modules where they identify themselves and each other. So if one computer goes down, when it resets the other computers will tell it who it is. Thus as we were putting a Dodge engine into the Jeep body all of these computers were more than a little bit confused. To start, Dave Harriton sifted through pages of the electrical manual for both the Jeep and the Dodge before modifying the wiring harness to accommodate the diesel engine, Power Wagon lockers, and diesel fuel pump.
Once the wiring was sorted out, Jordan stepped in and did his Geek Squad job on the multiple computers across the network within the Jeep. To simplify it for us he explained that the Jeep now thinks it has a Cummins diesel under its hood instead of the original 3.8L V-6 gas engine, and it also recognizes the four-wheel drive and 42-inch-tall tires and runs accordingly. Imagine it is like a giant office building where every desk knows what they do and what the other desks should be doing, then if you remove one desk and add a new desk you need to get all the other desks in order so they are not only reporting what they are doing, but also inviting the new desk to work amongst them. It's pretty amazing but also pretty complicated from the good old days when you just need 12 volts for lights, ignition, and your winch. In the end we drove this Jeep with no "check engine" lights on the dash at all. Of course the seatbelt light was blinking because we swapped to race harnesses, the airbag light wasn't happy because we changed to aftermarket seats, and for some reason the parking-brake light wouldn't go off, but otherwise the dash was warning-free the majority of the time.