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2002 Jeep Wrangler TJ - Synergy

Posted in Features on November 1, 2004 Comment (0)
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This Wrangler started life as an '02 TJ Sport, with every option available at the time. It came equipped with the 4.0L inline-six three-speed automatic transmission, Dana 44 rearend, and so on. It was purchased from the original owner with only 2,000 miles on the odometer in the hopes that it would make a great base for building a hard-core trail rig that still had all the creature comforts. Another plus for the '02 was the deep Mopar tranny pan available for the three-speed auto, which allows the Jeep to work at extreme angles without the transmission starving out, something the newer four-speed auto has a problem with.

The TJ's first stop was Drivetrain Unlimited in St. George, Utah, where James Stewart went to work installing parts from Currie Enterprises and 4 Wheel Drive Hardware. Currie Rock Ribz rocker-guard protectors not only protect the rocker panels and extend under the Jeep to the frame, they also feature heavy-duty DOM tubing extending 3 inches out from the body, affording extra protection from biting rocks. The Rock Crawler II rear bumper with the swing-away tire mount is hefty enough to carry a larger tire and wheel if needed. The Tail Bonez rear quarter-panel protectors mount to the Rock Crawler II rear bumper and wrap around the back corners, protecting those panels that always seem to get caved in first. Up front, the Noze Guard 42-inch bumper affords protection to the grille and radiator, and with some fabricating by Stewart, a place to mount the new Warn 9.5xp winch. Because the ground clearance on the TJ's 19-gallon fuel tank is so bad, Currie Enterprises offers a new 16-gallon tank that barely hangs below the bumper, allowing plenty of ground clearance.

Stewart wanted to install a 'cage inside, but was limited because the owners didn't want to lose much interior room. 4 Wheel Drive Hardware sent a sport cage made by O-R Fab, which installs without any drilling to the body or tub, allows the stock top hardware to be reused, and, with the addition of the floor-mounting kit, is very strong. The 'cage doesn't block vents or window cranks, nor intrude into the footwells.

The winch chosen for the project was Warn's new 9.5xp 9,500-pound model. With its low-profile and powerful 6hp motor, the 9.5xp delivers the fastest line speed under load and longest duty cycle of any Warn self-recovery winch. Built with motor and end-housing gaskets and full-face contact drum seals, the 9.5xp also resists water.

Once Craig Ross of Rockworx got hold of the Jeep, he ordered a pair of Rock Jock Dana 60s from Currie. The Rock Jock's third member is made of 206T6 aluminum and tips the scales at a measly 25 pounds, but still offers the Dana 60 strength and reliability. The Rock Jock is constructed with plenty of oil passages so the high-pinion gets lubricated correctly. The cover angle is a whopping 60 degrees, giving lots of ground clearance while allowing the use of any aftermarket Dana 60 cover. A carbon-steel jockstrap skidplate travels the length of the bottom and allows the Rock Jock to slide easily over the largest rocks. A bridge over the top supplies mounting points for control arms, traction bars, or any other thing used. Once the axle tubes are pressed into place, six bolts inserted through holes predrilled in the casting secure them. The Rock Jocks were equipped with Detroit Lockers and 4.88 reverse Precision gears from Reider Racing. Wilwood disc brakes handle the stopping power and are much lighter than most disc-brake kits.

Advance Adapters supplied the Atlas transfer case. The case was ordered with a Currie bolt pattern, which allows it to be rotated even higher than usual. With the automatic transmission, 4.88 gears, and 37-inch tires, it was decided that a 3.8 Atlas would work well. The Low-range ratio in rough terrain seems about perfect. Tom Wood of Tom Wood's Custom Driveshafts in Ogden, Utah, built the front and rear heavy-duty polished driveshafts.

All the arms in the four-link suspension and three-link front were constructed of 1.5x0.5-inch DOM tubing sleeved with 1.75x0.120-inch-wall tubing. This gives the arms tremendous strength. On one end of each arm, Craig used 0.75x0.75-inch QA1 Heim joints, while on the other end used urethane bushings. Fox 2.0 series 0.875-inch shaft 14-inch long-travel coilover shocks were mounted up front. These coilovers can be rebuilt and revalved, are nitrogen gas-pressurized, and are extremely high-quality. Coilovers also allow you to easily change your spring rates and ride height (to a point), so dialing in the suspension is easy. Craig also added a stiffening bridge from the top of the coilovers through the engine compartment. In the back, Rockworx coils were used, along with Rancho RS9000X nine-way adjustable shock absorbers. Rockworx built spring cans that trap the coils, as well as all the mounting bracketry both on the axle tubes and the Jeep. Craig also fabricated a high-clearance crossmember.

Craig used his extensive experience laying out the geometry of the suspension. The long-arm rear uses triangulated upper arms and dispenses with the Panhard rod. The three-link front uses long lower arms and a single long upper arm attached to the frame and Rock Jock's bridge. Currie's new aluminum Antirock antisway bars are also incorporated into the suspension system, allowing more opportunities for dialing it in.

Under the hood, the changes made include the addition of a K&N filter system, a Howe hydraulic steering ram, a pump and box, and a planned Kilby on-board air system. The K&N breathes much better, while still filtering the air. Howe makes an improved pump and pulley that fit the 4.0L; a much stronger, better sealed, and reworked steering box; and a hydraulic ram assist. The Howe system still allows some road feel through the steering wheel, yet steers with one hand on obstacles. Kilby's York compressor allows the use of air tools in the backcountry, as well as airing tires up as fast or faster than a large garage compressor; it's also a bolt-on proposition. With all the suspension modifications, a new exhaust system was in order. Performance Muffler in Montrose, Colorado, built a very nice after-cat system using a beautiful stainless-steel MagnaFlow muffler.

For rolling stock, new 17x9-inch bead locks from Pro Comp with 37-inch Xterrain tires were mounted up. Pro Comp is always engineering new products for rockcrawling and other off-road markets, and these wheels were prototypes. We're not sure if they're going to be available to the public, but we hope they are, as they have strong bead-lock rings and are comparatively light. The 37-inch Xterrains are super-heavy-duty and, during our photo shoot, showed surprising grip on the rocks and dirt in southern Utah. The extra-beefy sidewalls seemed to shrug off sharp rocks and ledges.

We drove this TJ during the photo shoot and a few other times, and the Jeep has lots of controlled articulation and stability. We've all seen radical super-travel 4x4s that can't climb the first obstacle on a trail because of incorrect geometry and not applying enough contact pressure on the rocks. The Rockworx Wrangler climbed everything we tried pretty easily. While the pieces used to put this Jeep together are some of the best available today, Craig and Rockworx made sure those pieces work together in a synergistic relationship. This Wrangler is definitely greater than the sum of its parts.

SPECIFICATIONS
Year/make/model: '02 TJ Sport
Engine: 4.0L I-6
Transmission: Stock
Transfer case: Atlas 3.8
Frontend: Currie Rock Jock with
  Detroit Locker
Rearend: Currie Rock Jock with
  Detroit Locker
Suspension: Rockworx three-link; rear:
  four-link
Ring-and-pinion: 4.88
Tires/wheels: Pro Comp 37-inch
  Xterrains/Pro Comp
  17x9-inch bead locks

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