Jeep JK Dana 30 Front Master Overhaul Kit, Spicer 10040478

This is Spicer part 10040478, the master overhaul kit for the reverse-rotation Dana 30 front axle used under the 2007-2018 Jeep Wrangler JK. Spicer is the axle manufacturer, so this is the supplier's own kit with Timken bearings and races rather than a mixed bearing assortment. Use it for a straight bearing and seal rebuild or when re-gearing the front axle to match larger tires.

As shown in the photos, the kit contains the tapered roller carrier bearings and races, the pinion bearings and races, the pinion seal, a crush sleeve, the pinion nut, a full spread of pinion depth and carrier shims, ten ring gear bolts, a tube of high-temperature silicone sealant and a packet of thread locker. Gear marking compound is not included.

JK front axles usually come apart for a whining or growling pinion bearing, a pinion seal leak after water crossings, or a gear swap to 4.56 or 4.88. Set pinion depth with the shims first, crush the sleeve slowly to reach preload, then shim the carrier for backlash and check the pattern on both drive and coast sides. Remember the reverse-rotation JK front uses gears cut for that rotation, so match the ring and pinion to the axle before setup.