Yukon Gear 4340CM Left Hand Inner Rplcmnt Axle For Dana 30 / 84-90 XJ / 97+ TJ / Uses 5-760X

Gear oil weeping out of the driver-side knuckle, a front end that will not pull on the left side in 4WD, or a bent inner shaft after a hard hit on the trail are the usual reasons a Jeep Cherokee XJ, Wrangler YJ or Wrangler TJ owner shops for a left-hand inner axle. Yukon Gear & Axle YA W38821 is the driver-side inner shaft for the Dana 30 front: 4340 chromoly, 27 splines into the differential, 16.63 inches long, with ears for the larger 5-760X series U-joint.

What the left inner shaft does in a Jeep Dana 30

The Dana 30 front in these Jeeps is a solid axle that steers, so each side is built from a long inner shaft and a short outer stub joined by a U-joint at the steering knuckle. The left inner shaft splines into the differential side gear, runs the length of the axle tube past the inner tube seal, and ends in the U-joint yoke inside the knuckle. Every bit of torque the left front tire puts down goes through it. The driver-side shaft on these axles is the shorter one, since the differential sits off center toward the driver side, so it is not interchangeable with the right side. Yukon builds this replacement from 4340 chromoly with cold roll formed splines and induction heat treating, aimed at Jeeps on larger tires, lockers or deep gears where a factory shaft can twist or snap.

Symptoms of a failed left inner shaft

• Left front tire does not drive in 4WD while the right side and the front driveshaft do
• A bang from the front axle under load followed by a free-spinning left wheel
• Gear oil inside the left knuckle or on the inside of the wheel, which points to a damaged shaft seal surface or tube seal
• Clicking from the left knuckle on turns, usually a worn U-joint, which may have stressed the shaft ears
• Splines at the differential end twisted, or the shaft visibly bent after a rock strike

How to confirm before you order

With the front on stands, the transfer case in 4WD and the transmission in park or gear, try turning each front tire. If the left one spins while the right is locked, pull the left unit bearing and slide the shaft assembly out of the tube. Look for a break at the U-joint ears, twisted splines at the inner end, and wear where the tube seal rides. Count the splines: this shaft is 27 spline. Check the U-joint size as well, since this shaft uses the 5-760X joint. Our Dana 30 front axle problems guide covers the other failures that show up at the knuckle and carrier, and the U-joint replacement walkthrough helps when you separate the shafts.

Fitment

The fitment table for YA W38821 lists the Dana 30 front in the 1984-2001 Jeep Cherokee XJ, the 1987-1995 Wrangler YJ and the 1997-2006 Wrangler TJ, all 4WD, left-hand side only. The product title calls out 84-90 XJ and 97-up TJ; the wider list comes from the fitment table. Yukon's technical note is the part to read carefully: this shaft uses the larger 760X style U-joint, and older axles built with the smaller 260X joint need a matching outer stub upgrade as well, such as the Dana 30 chromoly outer stub. It does not fit the 2003-2006 TJ Rubicon, which used a Dana 44 front. If you are not sure which joint your axle has, measure the old cap or send us your year and VIN. For the passenger side, use the matching right-hand Dana 30 inner axle. Other axle hardware is on our hard parts page.

Install notes

• Replace the inner tube seal while the shaft is out. The Dana 30/44/60 inner seal installer seats it square without damaging the lip.
• Slide the new shaft in slowly and support it so the splines do not drag across the new seal.
• Use a new 5-760X series U-joint to join it to the outer stub; do not reuse the old joint.
• Inspect the unit bearing for play or roughness and check the ball joints before closing up the knuckle.
• Refill the front differential with 75W-90 gear oil to the bottom of the fill hole, since some oil drains when the shaft is pulled.

If the differential itself is worn, the Dana 30 short-pinion master overhaul kit can be done with the shafts already out.

Which Jeeps does this left inner axle fit?

The fitment table lists the Dana 30 front in 1984-2001 Cherokee XJ, 1987-1995 Wrangler YJ and 1997-2006 Wrangler TJ, 4WD, driver side. It does not fit the TJ Rubicon, which has a Dana 44 front.

Will it work with my original U-joints?

It uses the larger 5-760X series U-joint. If your axle was built with the smaller 260X style joint, Yukon notes you will also need an upgraded outer stub so both ends match.

Is the left and right inner shaft the same?

No. The left shaft on the Dana 30 is shorter because the differential sits toward the driver side. This part is left-hand only, 16.63 inches long; the right side is a separate part.

What should I replace with it?

A new U-joint, the inner axle tube seal, and any worn unit bearing or ball joints you find while the knuckle is apart.

What gear oil goes back in the front axle?

Use 75W-90 gear oil and fill to the bottom of the fill plug hole. Add a friction modifier only if you run a clutch-type limited slip.

How many splines does it have?

27 splines at the differential end, which matches the factory Dana 30 side gears in these Jeeps.