Front Axle U-Joints

The joint that steers and drives

On a solid front axle with locking hubs or full-time 4WD, the axle shaft is split into an inner and outer piece joined by a universal joint that lives inside the steering knuckle. Every time the wheel turns, the joint flexes, and in four-wheel drive it also carries torque. Mud, water and the heat of a long trail day attack it, and a failed front axle U-joint can take the knuckle, hub and ball joints with it. The joints here are sized by cap diameter and width, which correspond to the axle: 1.062 inch caps on the 260 series for the Dana 30 and small Dana 44, 1.188 inch caps on the 760 series for the Dana 30, 35 and 44 with the larger shafts, 1.375 inch caps on the Dana 60 and AAM 9.25 front axles.

Picking the right series

• 5-260X: Dana Spicer's joint for the Dana 30 and the small-shaft Dana 44, 1.062 inch caps, 2.188 inch snap ring to snap ring. Crown's 8126637BC is the factory equivalent for the XJ, CJ5, CJ7, Comanche, Scrambler and YJ.
• 5-760X: the 1.188 inch cap joint for later Dana 30s and the Dana 44, also 2.188 inch wide. Crown's 8126638SP covers the JK, TJ, YJ, XJ, ZJ and Wagoneer with the same caps.
• 5-7166X: the JK Rubicon Dana 44 joint at 2.405 inches snap ring to snap ring. It does not interchange with the 760 series.
• Dana 60 and AAM 9.25: 1.375 inch caps, used on Ford, Dodge and GM three-quarter and one-ton trucks. The SPL55-3X replaces the discontinued 5-806X.

Measure the old joint's cap diameter and overall width, or identify the axle from its cover shape and tag, before choosing. The same model Jeep used both 260 and 760 series depending on year.

Sealed, greaseable or extreme duty

Factory replacement joints from Dana Spicer and Crown are mostly non-greaseable, permanently lubricated units with improved seals, often described as perma-lube. They have a solid cross with no grease channel, which makes them stronger than a greaseable joint of the same size, and they suit most trail Jeeps. Greaseable joints, like the Alloy USA extreme-duty Dana 44 joints with a Zerk in each cap, let you flush water out after a wet trip, which matters if you ford streams regularly, but the grease passages reduce cross strength slightly. Extreme-duty or X-joint designs from Alloy USA and CTM Racing use forged caps and needle bearings or bushings for Jeeps on 37 inch tires and lockers, where the stock joint is the fuse. Keep in mind that making the joint stronger moves the failure point to the axle shaft or the knuckle, so upgrade in balance.

Replacement tips

Replacing a front axle U-joint means pulling the hub, bearing and axle shaft, so inspect the unit bearing, ball joints and axle seals while everything is apart. Use a press or a ball joint press adapter rather than a hammer, support the yoke ears evenly, and install the snap rings fully. Grease greaseable joints until fresh grease purges every cap seal, and check the shaft runs true before reassembly. Torque the hub bolts and axle nut to the manufacturer's specification. Steering and drivetrain parts affect safety, so if you are not equipped to press joints, have a shop do it. Confirm the joint matches your axle and year before choosing.