Revolution Gear & Axle 07-18 Wrangler JK Dana 30 Chromoly Discovery Series Front Axle Kit

The Revolution Gear & Axle DC-D30-JK-1350 replaces every front axle shaft in the Dana 30 under a 2007-2018 Jeep Wrangler JK Sport or Sahara with 4340 chromoly, and swaps the small factory-size U-joints for larger 1350-style Spicer 5-7166X joints. It is built for the non-Rubicon JK owner who has gone to bigger tires, added a front locker or limited slip, or already broken a stock shaft or joint and does not want to do it twice.

What the front shafts do in a JK Dana 30

The JK's Dana 30 is a high-pinion, reverse-rotation front axle with 27-spline shafts. Each side has a long inner shaft that splines into the carrier and a short outer stub that drives the wheel through the unit bearing, joined by a U-joint inside the knuckle so the wheel can steer. The stock setup uses the smaller 5-760X-size joint, and on 35 in. tires that joint and the outer stub's ears are where the axle usually lets go. This kit includes two 4340 chromoly inner shafts, two 4340 chromoly outer stubs, two Dana Spicer 5-7166X joints and eight full-circle snap rings. The bigger joint is the main reason to pick the -1350 version over the base kit, which keeps the 5-760X size.

Symptoms that call for this kit

• A bang under load in 4WD, then one front wheel no longer pulls: a broken outer stub, inner shaft or U-joint.
• Clicking or a rhythmic pop from the front corner when turning in 4WD, the classic worn front axle U-joint sound.
• Rust-streaked or dry U-joint caps, or play you can feel when twisting the outer stub by hand.
• Gear oil weeping from behind the knuckle, pointing to a failed inner tube seal that needs the shafts pulled anyway.
• Adding a front traction device or 35s to a JK that still has factory shafts and joints.

How to confirm before buying

With the front end raised and the transfer case in neutral, spin each front wheel and watch the U-joint through the knuckle opening, then rock the outer stub to check for joint play. A wheel that will not drive with the other side held usually confirms a broken part on the free side. Our Dana 30 front axle problems and rebuild cost guide covers JK-specific weak points such as bent tubes on big tires, and U-joint replacement symptoms and cost helps separate a joint problem from a wheel bearing.

Fitment

Revolution Gear lists the DC-D30-JK-1350 for 2007-2018 Wrangler JK Sport and Sahara models, 2-door and Unlimited, with the factory Dana 30 front and 27-spline axles. It does not fit the Rubicon, which uses a Dana 44 front with 30-spline shafts and needs the JK Rubicon Dana 44 chromoly front axle kit. A few JKs have had axles swapped over the years, so read the axle tag on the differential cover or send us the year and VIN and we will confirm before it ships. More parts for the axle are under rebuild kits.

Install notes

• The kit comes unassembled. Press the 5-7166X joints into the shaft ears and seat all eight full-circle snap rings before installing; a set of snap ring pliers and a U-joint press save a lot of frustration.
• Pull the wheel, caliper and rotor, unplug the ABS sensor, and unbolt the unit bearing from the back of the knuckle to slide the old shaft assembly out.
• Seals are not included. Fit new inner axle tube seals with the Dana 30/44/60 inner axle seal installer tool, and feed the new inner shaft in carefully so the spline does not cut the lip.
• If the carrier is coming out for a regear, JK fronts need reverse-cut gears such as the Revolution Dana 30 JK reverse 4.56 ring and pinion, and moving from a 3.54-or-lower ratio to 3.73 or numerically higher needs the JK Dana 30 3.73-and-up carrier case. Our JK regear kit buyer's guide explains the carrier break.
• Torque the unit bearing bolts to factory spec and top off the front differential with gear oil before driving.

Does this fit a JK Rubicon?

No. The Rubicon uses a Dana 44 front with 30-spline shafts. This kit is for the Dana 30 front with 27-spline shafts found on JK Sport and Sahara models.

What is the difference between this and the base Dana 30 JK kit?

The shafts are the same 4340 chromoly, but this -1350 version uses the larger Spicer 5-7166X 1350-style U-joints instead of the smaller 5-760X joints. The bigger joint is stronger and is the part that usually breaks first on a stock front.

Can I reuse my old U-joints?

It is not recommended. The kit is built around the 5-7166X joints it includes, the smaller factory-size joints are what this upgrade replaces, and old joints are a common failure point anyway.

Do I need new seals?

Yes. Axle seals are not included. Replace the inner tube seals whenever the shafts come out, or gear oil can migrate into the knuckle and unit bearing.

Will chromoly shafts make my axle unbreakable?

No. They move the weak point. With chromoly shafts and bigger joints, the housing, ring and pinion or ball joints can become the next limit, so pair the upgrade with sensible tire size and gearing.