The Unlimited Rubicon's longer wheelbase settles the ride on- and off-road--a trait that should attract buyers who didn't care for the standard Wrangler's choppy demeanor. But what really sets the Wrangler Unlimited Rubicon apart from the typical factory offering is hard-core off-roading hardware that isn't so obvious. The Unlimited is equipped with heavy-duty Dana 44 axles front and rear, both of which have 4.11:1 gears and air-actuated Tru-Lok locking differentials.
The Tru-Lok air lockers are cool: In 2WD or 4WD High, they operate like conventional limited-slips. But in 4WD Low, the driver can push a button on the dash that engages the differential's air-locking mechanism, mechanically locking the axle shafts together so all four wheels are driven at the same speed. The air-locking diffs set the Unlimited apart from every other TJ.
Jeep's Tru-Lok differentials, built by Tochigi Fuji Sangyo, require just five pounds of pressure to operate, making their operation silent. With such stealth, it's easy to impress even the most diehard off-roaders when the "stock" Unlimited Rubicon suddenly appears unstoppable.
Another great advantage the Unlimited Rubicon has over all other Wranglers is the ultra-low-geared NV241 Rock-Trac transfer case. The standard Jeep Rubicon transfer case has a ratio of 2.27:1, while the Unlimited's gearing is 4.0:1. The deeper low-range gearing allows you to literally crawl up and down steep terrain, as we saw during our test drive over Moab's slickrock.
Whether driving the manual six-speed or the four-speed automatic, the gearing and wide torque band of the 190-horsepower, 4.0-liter Power Tech inline-six makes the 2005 Unlimited Rubicon a hard-core outdoorsman's dream ride. If it can't make it through or over the terrain, nothing else short of a tank will.