Buy Low, Build Big
A 2WD Jeep Wrangler JK? As oxymoronic as the idea may seem, Jeep offers and sells quite a few of these models each year. We, of course, have never really had a use for such a vehicle since it would lack such key components as a front axle and a transfer case, which we rely upon quite heavily in our trade. So why are we now speaking of the 2WD JK as if it's something you should know about? Because we just made one a lot better.
There were a lot of reasons we decided to start a buildup with a 2WD JK instead of a 4WD JK. The biggest reason, however, was cost. A fully equipped Wrangler Unlimited Rubicon 4x4 sells for more than $30,000. A 2WD Unlimited X model goes for about $10,000 less. Being that we intended to ditch the stock axles and transfer case for aftermarket units anyway, it seemed silly to pay so much extra for equipment that we wouldn't even use. Rather, we were able to apply the difference to a set of ARB-equipped Dynatrac ProRock 60s and an Atlas four-speed transfer case, both of which will offer more strength and ability than their factory counterparts.
Converting the 2WD JK to use a 4WD front axle was somewhat of a bolt-up job. 2WD JKs are fitted with an empty tube "axle" that is equipped with the same configuration suspension mounts as found on the factory 4WD JK axle. Since we had Dynatrac set up the ProRock 60 axles with the appropriate mounts for the JK suspension, it was simply a matter of hanging the front axle using new Rancho control arms. Of course, we'd still need to mount the Atlas transfer case behind the stock transmission and have new driveshafts made to mate up the axles and Atlas 'case, but for the most part the 4WD conversion played out as a near bolt-on installation.
The new Rancho long-arm suspension system is designed for '07-and-later 4WD Jeep Wrangler JKs. Unique to the Rancho long-arm JK system is the reverse tri-link design, which eliminates use of a rear track bar. The system is designed to accommodate up to 37-inch tires; however, 40-inch tires are an easy possibility with the addition of slightly taller custom coil springs. The Dynatrac axles are equipped with 35-spline axleshafts, ARB Air Lockers, and 5.13 gears, so we shouldn't have any issues in regard to strength or gearing even with 40-inch tires in place.
Available for both left and righthand vehicle applications with centered rear differentials, the Atlas 4SP uses a six-pinion, helical-cut planetary gear assembly that's situated within a reduction housing mated to a main case. The main case and reduction housing are operated using a twin-stick shifter and can be shifted independently to achieve front- or rear-only operation. The gears in the main case are synchronized for quieter operation and shift-on-the-fly capability; however, the planetary assembly is not and can only be shifted when the vehicle is stopped. The Atlas 4SP is available in two Low-range offerings, including 1:1, 2.0:1, 2.72:1, and 5.44:1 or 1:1, 2.72:1, 3.8:1, and 10.34:1.
Ready to complete the 4WD JK conversion and have the Rancho suspension components installed, we traveled to Off Road Evolution, which is well-versed in modifying and building Jeep Wrangler JKs. From start to finish, the conversion lasted a few days' time, not including an extra day or so to also install front and rear bumpers, rocker guards, and fender flares. Check out the photos and captions to view the conversion process.