YJ WRANGLER + UNIMOG AXLES = TRAIL SLAYER
BY Harry Wagner
PHOTOGRAPHY HARRY WAGNER
KRIS WIX WASN’T ALWAYS a wheeler. “I grew up in the mountains of Truckee, California,” he says, “and we get a lot of snow in the winter. I was used to driving 4x4s, but seven years ago I couldn’t even get a pitman arm off a steering box.”
Since that time Kris has jumped in with both feet, turning what was once daily transportation into a dedicated trail slayer. He is the second owner of his ’93 YJ, having driven it throughout his college years with his girlfriend. The two have since married and started a family, and just as their lives have changed so has the YJ. Kris bought a tube bender, a notcher, and Bend Tech software, and with the help of his friend Jeremy Winters he built a grille hoop and a full rollcage. “I could have paid someone to build me a cage,” says Kris, “but instead I invested the money in a tube bender.”
Unimog 404 portal axles were added front and rear, with factory air lockers and 7.56 gear reduction between the ring-and-pinion and portal boxes. The axles required a host of other modifications in order to fit under the Jeep, starting with pinion conversions and disc brake upgrades from Exaxt and continuing on to details like a Dodge master cylinder and an RCI fuel cell fitted with the stock YJ fuel pump. Kris also converted his suspension to coilovers and links at the same time, and stretched the wheelbase to 114 inches.
His previous daily driver Jeep was under house arrest for several months as he tore it down to perform these modifications in the evenings after work. The maiden voyage was in Johnson Valley right before the 2009 King of the Hammers. Kris recalls, “I broke the track bar off the axle at the top of Sledgehammer and almost didn’t get it off the course before the race began!” He has since worked out all of the bugs and has been enjoying the hardest trails he can find ever since.
1 Under the hood the tired 4.0L is surrounded by tubing, the Fox Shox remote reservoirs, and a PSC steering pump and aluminum reservoir. “It doesn’t make enough power to get me in trouble,” says Kris Wix.
2 Steering 404 Unimog axles are used at each end of the Jeep. “I had enough spare front parts that I figured I would just add rear steer,” Kris explains. Conventional steering would require the track bar to go from the driver side of the frame to the passenger side of the axle, but the full hydraulic steering allowed him to reverse that arrangement and better package the suspension.
3 The rear suspension uses a triangulated three-link with 16-inch-travel Fox coilovers and air bumps, while the front suspension consists of a conventional three-link with a track bar and 14-inch travel Fox coilovers. Kris built all of his own links out of 0.250-wall tube and capped them with Rubicon Express Flex Joints.
4 Downstream of the AW4 automatic transmission, an Advance Adapters Atlas II transfer case was added with a 4.3:1 low range. Also visible is the 2-gallon air tank used in conjunction with a Viair compressor to actuate the air lockers and air up tires.
5 Kris cut the rear of the frame behind the front seats and replaced it with tube to gain some uptravel. It is a challenge to balance low ride height and uptravel with portal axles, particularly Unimog axles where the differential is almost centered both front and rear. Rolling stock consists of 42-inch Iroks on Hummer H2 beadlock rims. The fronts are DOT tires, the rears are stickies. Kris says, “I could only afford two sticky tires when I bought them, and now I can’t find any more.”
1993 JEEP WRANGLER YJ
ENGINE: 4.0L I-6
TRANSMISSION: AW4 4-speed automatic
TRANSFER CASE: Advance Adapters Atlas II
FRONT AXLE: Unimog 404, factory air lockers, 7.56 gears (3.54 diff and 2.13 hub)
REAR AXLE: Unimog 404, factory air lockers, 7.56 gears (3.54 diff and 2.13 hub)
SPRINGS & SUCH: 14-inch-travel Fox 2.0 coilovers w/ 250 over 350 in-lb Eibach springs (front), 16-inch-travel Fox 2.0 coilovers with 200 over 300 in-lb Eibach springs (rear), and Fox air bumps
TIRES & WHEELS: 14/42-17LT Super Swamper Iroks on 17-inch Hummer H2 rims
STEERING: Full hydraulic with PSC double-ended ram
OTHER STUFF: Rear steer, owner-built custom cage, Warn winch, Viair compressor and tank, Exaxt disc brake conversion, GenRight front tube fenders