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2007 Jeep Wrangler JK Unlimited - RubiCrawler

Posted in Features on February 1, 2011
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Every vehicle has a purpose. This 2007 Jeep Wrangler JK Unlimited's purpose is testing parts for Advance Adapters, most notably the company's new RubiCrawler auxiliary gearbox designed for Jeep Wrangler JKs and TJs.

Advance Adapters in Paso Robles, California, built its 2007 Jeep Wrangler JK Unlimited as an R&D test mule. To date it has assisted in R&D with the RubiCrawler auxiliary gearbox as well as the Atlas four-speed transfer case.

The Advance Adapters RubiCrawler auxiliary gearbox uses a six-planetary gearset within a new cast housing. The new housing replaces the empty tail housing that mates the 42RLE auto trans to the NVG241 and NVG241OR transfer cases in Jeep Wrangler JKs, and the NVG241OR and NP231 transfer cases in Jeep TJs. Once in place it creates two low ratios; the factory 2.72:1 transfer case low ratio and the RubiCrawler 7.40:1 low ratio.

Being a test mule, the RubiCrawler JK had to be built tough all around. It not only tackles difficult trails repeatedly but is also subjected to multiple drivers with different driving styles (hard and harder; it is a test mule...). With this in mind the Advance Adapters crew installed a Rubicon Express 5.5-inch long-arm suspension system along with a set of 14-inch-travel Sway-A-Way coilover shocks up front. The arrangement clears a set of LT325/80R16 (37-inch-diameter) Pro Comp Xterrain Radial tires mounted on 16x10 Pro Comp Extreme Alloys Series 1079 wheels with 4.5 inches of backspacing.

To combat the rocks a set of Poly Performance rock sliders and a full Poly Performance skidplate system was installed. Hanson bumpers guard the front and rear of the RubiCrawler JK. The front Hanson unit is fit with a T-Max EWI 12,000-pound winch with Master-Pull synthetic winch line and aluminum fairlead. The bumper features integrated D-rings and light mounts. The rear Hanson bumper and tire carrier supports a full-size spare tire.

ARB Air Lockers and 5.13 gears are installed in the front and rear pumpkins. The front axle is a hybrid Dana 44 unit equipped with Dana 60 king-pin outers. The rear is a Dana 60 unit. A PSC steering box and pump are in place to assist steering the 37-inch Pro Comps.

This JK's time of testing parts isn't anywhere near being done. It seems that Advance Adapters always has something new up its sleeve, and we're certain that if it's a JK-related part it will be installed on this JK at one point in time before reaching final production.


Vehicle: 2007 Jeep Wrangler JK Unlimited
Owner: Advance Adapters
Hometown: Paso Robles, CA
Engine: 3.8L V-6
Induction: EFI
Transmission: 42RLE automatic
Transfer Case: NVG241, RubiCrawler
Low Range Ratio: 2.72:1, 7.4:1
Front End: Hybrid Dana 44 w/ Dana 60 outers, Dynatrac cover
Rear End: Dana 60, Dynatrac cover
Ring And Pinion: 5.13
Front Differential: ARB Air Locker
Rear Differential: ARB Air Locker
Suspension: Rubicon Express long-arm with Sway-A-Way coilover shocks
Tires: LT325/80R16 Pro Comp Xterrain Radial
Wheels: 16x10 Series 1079 Pro Comp Extreme Alloys
Backspacing: 4.5 inches

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