Yukon Gear Chromoly Inner Front Axle for Dana 30 30 Spline Right Hand 34.5in Long w/Locker

A twisted or snapped front inner shaft is the classic way a Jeep Wrangler JK on bigger tires ends a trail day, and the long passenger side shaft on the Dana 30 is the one that takes the most wind-up. Yukon YA W38837 is a 4340 chromoly replacement for that right-hand inner shaft, 34.5 in. long, with 30 splines at the differential end. It is built for a JK front Dana 30 that has been fitted with a 30-spline aftermarket locker, and it is the shaft to buy if you are building that axle up instead of patching it with another stock 27-spline part.

What the inner axle does in a Dana 30

On a solid front axle, each side has an inner shaft that runs from the differential side gear out through the tube to the U-joint at the steering knuckle, and an outer stub that turns the hub. The inner shaft is the long, thin section that has to carry all the front torque the differential sends that way. The right side on this axle is the long one, so under a hard climb with a locker engaged it twists more than the short left side. Yukon makes this shaft from high-tensile 4340 chromoly with cold roll formed splines and induction heat treating, which lets it flex and return instead of taking a set or cracking at the spline. Going to 30 splines also puts more metal at the inboard end, the spot where stock 27-spline shafts most often fail.

Symptoms of a damaged front inner shaft

• A bang from the front axle in 4WD followed by no front pull on that side
• Splines on the inboard end that are twisted, stepped or stripped when the shaft comes out
• A clicking or binding feeling when turning in 4WD, often from a failing U-joint at the end of a bent shaft
• Gear oil running out the tube onto the knuckle, from a seal cut by a shaft that was bent or dragged in

How to confirm before you buy

Pull the shaft and look at both ends. Sight down its length on a flat surface to check for bend. Count the inboard splines and measure the overall length, because a 27-spline factory shaft and this 30-spline shaft will not go into the same side gear. Our Dana 30 front axle problems guide covers the other wear points to check while it is apart, and chromoly axle shafts vs stock explains when the upgrade is worth it.

Fitment

This shaft is listed for the front Dana 30 in 2007-2018 Jeep Wrangler JK with an aftermarket locker that uses 30-spline side gears. It is not for a stock JK open differential or any carrier with 27-spline side gears, and it is the right side only. The left side uses a shorter shaft sold separately, and both sides need 30-spline shafts to match a 30-spline locker. The outer end takes a 1350-series 7166 U-joint. Confirm your locker spline count and measure the old shaft before ordering, or send us your year, VIN and locker part number and we will check it. If you are regearing at the same time, the JK Dana 30 4.56 ring and pinion and JK Dana 30 master overhaul kit fit the same axle, and our JK regear kit guide walks through the whole job.

Install notes

• Pull the hub and knuckle-side hardware, then slide the old inner shaft and joint out of the tube.
• Install the new 1350-series U-joint between this shaft and the outer stub before the assembly goes back in. Our U-joint replacement guide covers pressing it in without damaging the caps.
• Replace the inner tube seal while the shaft is out, and seat it square with an inner axle seal installer tool. Support the shaft by hand on the way in so the splines do not cut the new seal.
• Engage the splines in the locker side gear gently. If the carrier is out, a Dana 30-80 housing spreader makes carrier removal and preload work easier.
• Top off with 75W-90 gear oil, then check that the locker engages and the shaft turns freely with the wheel off the ground.

Find more axle shafts and hard parts in our hard parts section.

Will this fit a stock JK Dana 30 with the factory open differential?

No. This shaft has 30 splines at the inboard end and is listed for use with an aftermarket locker only. A factory JK open carrier uses 27-spline side gears.

Is this the long or short side?

It is the right-hand inner shaft at 34.5 in. long. The left side is a shorter shaft sold separately, and both sides must be 30 spline to match a 30-spline locker.

What U-joint does it use?

It takes a 1350-series 7166 U-joint at the outer end. Plan on a new joint when you install the shaft.

Why chromoly instead of a stock shaft?

Yukon builds it from 4340 chromoly with cold roll formed splines and induction heat treating, so it handles the twist from bigger tires and a locked front axle better than a stock shaft.

Which years of Wrangler does it fit?

It is listed for the 2007-2018 Jeep Wrangler JK front Dana 30 with a 30-spline aftermarket locker. Measure your old shaft and confirm your locker spline count before ordering.

Do I need to replace the inner axle seal?

Yes, it is good practice. The seal is usually damaged when a shaft comes out, and a leaking seal sends gear oil out to the knuckle and U-joint.