Yukon Gear 4340CM Rplcmnt Outer Stub For Dana 30 and 44 / Scout / and CJ / Uses 5-760X U/Joint

A Jeep CJ5 or CJ7 or an International Scout II that snapped a front outer stub in the rocks, or one with a stub whose splines have gone sloppy in the locking hub, needs a replacement that will hold up better than the original. Yukon YA W39105 is a 4340 chromoly front outer stub axle for the Dana 30 and Dana 44 front axles in those trucks. Yukon lists it at 8.72 inches long with 27 splines, made to accept a 5-760X series U-joint, with cold roll formed splines and induction heat treating.

What the outer stub does in a Dana 30 or Dana 44 front axle

In a solid front axle with steering knuckles, each axle side is two pieces joined by a U-joint. The long inner shaft runs from the differential side gear out to the knuckle, and the short outer stub runs from that U-joint through the spindle to the locking hub. The joint lets the wheel steer while still being driven. On a CJ or Scout with manual locking hubs, the outer stub's splines engage the hub only when the hubs are locked, so in two-wheel drive the stub is just along for the ride. In four-wheel drive it carries the full torque for that wheel through the tightest bend of the joint, which is why stubs and U-joints are the classic front axle failures when you add bigger tires, a locker or lower gears. The outer stub also has the bearing surface for the spindle bushing or needle bearing, so a worn stub can make a new spindle bearing fail early.

Symptoms of a worn or broken outer stub

• A loud bang in four-wheel drive followed by no drive to one front wheel: the stub, the U-joint or both have broken.
• Clicking or popping when turning in four-wheel drive, usually a failing U-joint that can take the stub ears with it.
• Hub that will not engage cleanly, or slop felt at the hub, from worn stub splines.
• Grease or gear oil flung inside the wheel and a rough spindle bearing, often with a scored bearing surface on the stub.

These trucks predate OBD-II, so there are no trouble codes; diagnosis is hands-on.

How to confirm it before you buy

With the front end on stands, lock the hubs and put the transfer case in neutral. Rotate one front wheel while someone holds the driveshaft and feel for clunks or binding. Then pull the hub, spindle nuts and spindle and slide the axle assembly out to check the U-joint and both stub ends. Twisted or rounded splines, cracked U-joint ears or a pitted bearing surface all mean a new stub. Our Dana 30 front axle problems and rebuild cost guide covers the rest of the axle, and our Dana 30 vs Dana 44 comparison helps if you are not sure which axle your truck has. If the ring and pinion bearings are worn while you are in there, the Dana 30 front master bearing kit covers the carrier and pinion.

Fitment

Yukon's fitment table lists this standard-rotation stub for the 1971-1983 Jeep CJ5 and 1976-1986 Jeep CJ7 with the Dana 30 front, the 1971-1974 International Scout II with either the Dana 30 or Dana 44 front, and the 1975-1980 Scout II 4WD with the Dana 44 front. It is a 27-spline, 8.72 inch stub for the 5-760X joint, so measure your old stub and count its splines before ordering, especially on a truck that may have had axle swaps. Reverse-rotation and later Jeep Dana 30 axles use different stubs. If you are unsure, send us your year and VIN. While the axle is apart, the Motive Gear R30RMKT Dana 30 front master bearing kit is a Timken-based alternative for the carrier and pinion bearings.

Install notes

• The U-joint is not included. Use a new 5-760X series joint and press it in squarely with a frame press such as the OTC 7248 U-joint C-frame press so the stub and shaft ears are not sprung.
• Inspect the spindle bearing or bushing and replace it if the old stub was worn; a new stub in a rough bearing will not last.
• Clean and repack the wheel bearings, set preload per the factory procedure, and check that the hubs lock and unlock smoothly.
• When the inner shafts come out, install new inner axle seals with the Dana 30/44/60 inner seal installer so they seat straight.
• Top up the differential with 75W-90 gear oil to the bottom of the fill hole.

A worn-out front diff can be done at the same time with the Dana 30 front master overhaul kit.

Which Jeep CJ years does this outer stub fit?

Yukon lists it for the 1971-1983 CJ5 and 1976-1986 CJ7 with the standard-rotation Dana 30 front axle. Count the splines (27) and measure the stub (8.72 inches) to confirm.

Does it fit my Scout II?

Yukon lists the 1971-1974 Scout II with a Dana 30 or Dana 44 front and the 1975-1980 Scout II 4WD with a Dana 44 front.

Is a U-joint included?

No. The stub is sold alone and uses a 5-760X series U-joint, which you install when you join it to the inner shaft.

Will this fit a Jeep Wrangler YJ, TJ or Cherokee XJ?

Those Jeeps use a different Dana 30 with different stub dimensions, so this part is not listed for them. Check the parts for your exact model instead.

Should I replace both sides?

If one stub broke from tire size or a locker, the other side has seen the same load. Many owners replace both or go to a full chromoly axle kit.