In stock form, the Jeep JK Rubicon offers vast improvements over earlier Wranglers. Locking differentials and larger ring-and-pinion gears are two of many benefits found in the Rubicon. So, why would one consider an axle upgrade for an already capable vehicle such as the JK Rubicon? The answer lies in the details.
Yes, the Rubicon offers better axle gears and quality lockers. However, the axle housings that contain those upgrades are still significant weak points and are only slightly better than a mid-'90s Wrangler YJ. We view these flaws simply as a reason to start looking to the aftermarket for a healthy upgrade.
In the old days, swapping a set of street legal Dana 60s into your Wrangler was quite the formidable task. There were plenty of roadblocks to overcome. To name only a few: you had to consider shortening tubes, fabricating control arm and spring brackets, and, of course, regaining a balanced brake system. Thanks to a very limited group of aftermarket companies, the Dana 60 Wrangler has become much more of a reality and much less of a headache. At the front of the pack is Currie Enterprises of Anaheim, California. Currie has been in the axle business longer than any one company and it shows in its latest offering for the Jeep JK. When we say the Currie high-pinion RockJock axles are a direct bolt in, we really mean it in every sense of the word. From the trademark slanted front cover down to the most simple details, like the supplied vent hose extension and sensor wire clamps, the RockJock "package" covers it all.
In addition to the hardware benefits you will see in this article, it should not be forgotten that the Currie RockJock front axle cures a growing problem for lifted Wranglers. There are an increasing number of JK owners who are finding a front driveline vibration problem, which proves near impossible to cure without the addition of manual hubs. Before you offer up the obvious responses like "change your pinion angle" or "check your driveshaft balance," let us point out that on this particular JK, all of the obvious was checked, adjusted, or changed, and checked again. Despite trying multiple driveshafts, yokes, caster settings, etc., this JK could not rid itself of a front driveline vibration when moving faster than 60 mph. It was only after the driveline would be removed that things became smooth and vibration free. The installation of the Currie axle assemblies cured this problem forever, therefore relieving ourselves of the daily shakes on the drive to work. The value of this improvement alone is immense. Follow along as we cover a few of the high points of a typical RockJock axle build.
The JK already had electric...
The JK already had electric lockers and we had become spoiled by their silent and maintenance-free performance. We've used other types of lockers in the past and had very good success. However, the overwhelming benefits of the Eaton E-Locker were impossible to pass up for this project. The E-Locker comes with a complete wiring harness and illuminated rocker switches. Strength is not a concern. The dependability of the Eaton E-Locker is so good that AM General and the U.S. military used them in the H1 Hummer with tremendous success.
If there was ever a reliability...
If there was ever a reliability concern for a particular ring-and-pinion supplier, the brand in question would never find a home in a Currie-built axle assembly. The ring-and-pinion sets from Motive Gear provide consistent setups and no annoying gear noise when installed by one of the experts at Currie Enterprises. The perfect pattern you see in the photo is routine for Motive Gear products and the 5.38 ratio runs as quiet as the original Rubicon 44s.
Rocky trails can deal a rough...
Rocky trails can deal a rough hand to standard Dana 60 differential covers. One nice feature of the canted profile of the RockJock is the lessened exposure for the edges of the cover and the cover bolts. Although the shape of the RockJock center housing eliminates much of this issue, Currie pays special attention to details as simple as reshaping the lower edge of the new cover.