C4x4.com

As an upgrade to the stock Dana 30 front axle that the YJ came from the factory with, the Dana 44 is a good choice. It is a good bit stronger and more easily modified than the D30 right out of the box and, with a few upgrades, can be considered worthy of 35” to 37” tires and reasonable driving demands.

Many folks jump right to a D60 to get the strength that the one ton axles offer but the strength comes at a price. The loss of clearance, added weight and up front cost of a D60 are a bit much for a 35” tire in my opinion. A 37” tire makes the case for a D60 a bit stronger and a 38” tire pretty much steps over the line, but there are tons of folks running D44s with 37” tires and upgraded axle shafts and u-joints and having great success. However, if you want the ability to pin the throttle with abandon and not worry about snap-crackle-pop, pony up for a D60 to begin with and live with the size and cost. In the end you will be happier and you can increase tire size without starting over with a new axle build.

I will never run bigger than 37” tire and likely I would be very happy with a 35” tire. I drive with grace and caution compared with many folks. However, I still wanted to hedge my bet by upgrading the Waggy D44 with high strength alloy axle shafts and stronger than stock u-joints.

One of the leading companies in this market is Alloy USA. Based in Southern California, Alloy USA has this to say about their axle shafts:

High tensile strength 4340 Chromoly is heat-treated twice to produce these heavy-duty axles that are up to 30% stronger. Exclusive 10-Year warranty. Shafts come completely assembled with inner and outer shafts, U-joints and full circle clips. Sets include both passenger and driver sides.

I also had the chance to sample the very new X-Joint u-joint which has an 8620 heat treated alloy cross with greaseable needle bearings for the needs of daily drivers. They will be offering another version without the needle bearings, but that will require more maintenance and will likely be aimed at the comp guys/trailered rigs. These u-joints come with full circle clips and are pre-installed into the axle shaft sets. They carry a 5 year warranty.

alloy usa jeep axles

I removed the stock Waggy shafts which I will upgrade with the newer Spicer joint and keep as spares. The install of the Alloy shafts was pretty straight forward. I swapped over the seal and seal retainer that sits on the stock axles to the new shafts. Notice how in the two pics comparing the stock shafts to the new axles that the Alloy USA shafts do not neck down at the splines? Added strength there. Also, you will see in the pics that I threaded the zerk fittings in while the shafts were out of the Jeep only to find they will not pass through the knuckle that way. Out they came so I could get the shaft into the axle housing. Be careful as you pass the inner end of the axle shaft in through the inner seal at the diff housing. You need to lift the shaft up some so it does not damage the seal. One thing I came across was a bit of interference with getting the axle ears and u-joint caps to slide through the outer knuckle. I had to tap the axle in place with a piece of 2x4 on the driver side, but on the passenger side, even a 5 pound sledge was not getting it to go through without more pounding then I wanted to do. I ended up looking at the points of interference which seemed to be the top edges of the caps and taking a fine grit sanding disc on my angle grinder to the high spots. I did this very gradually and carefully and test fit every so often till it slid through with a reasonable amount of tapping. I bet that I will have to get behind the knuckle and tap them out of there if I ever need to remove the shafts.

Once in place, I installed the zerk fittings and reinstalled the spindle and hub/rotor assembly.

This upgrade adds a great deal to my piece of mind and will keep breakage to a minimum if not eliminate it altogether. Of course, that depends on how sane I stay with that gas pedal. Those Mustang H.O. motors sound soooo good when they are prodded a bit!