Like it says, what is the weak point of the New Generation rear axle. Some guys say it's no better than the old ones. One shop that modifies JKs said he has never seen one fail and wouldn't spend the money on Alloys. With a 4-link truss and Superior shafts is it a reliable unit for 37s and an easy skinny peddle? For those that have broke one, what failed and why? It's well known what the front 44 needs, but what about the rear?

 

the weak link in a factory rubi 44 is the rear locker. i went through a couple of them before getting an arb installed. if you play really hard and or run really big tires, i have seen the factory shaft flanges bend and i have seen the housing bend as well. if you run 5.38's, the pinion will be really small and, depending on how big of a tire you run and how hard you play, this can be a weak point as well. before upgrading to a prorock 60, this is what i was running and ultimately broke. but then, i was running 40" toyos. if you go easy on the skinny pedal, you should be just fine with 37's.

 

How would you rate the factory rear axle shaft? Is that something worth upgrading to Chromoly if all your running is 35s or 37s?

I recently broke my front shaft, but it broke at the u-joint and killed the lobes. Seems like the rear, since it lacks u-joints, wouldn't have this same weak spot.

 

for the most part, i think that the rear shafts are fine. as mentioned, i have seen where the flanges can get bent but, i've only seen maybe one that has actually broken. upgrading them to chromoly isn't a bad idea but, i'd have no problems waiting until it's really needed.

up front, that's a whole different issue altogether. the factory front shafts use c-clips and over time, these can work themselves loose and that's ultimately what leads to breaks at the yoke - the most common axle shaft breaks you'll see up front. chromoly shafts will have full circle clips and for this reason alone, they are good to have up front.

 

As I posted before, I've been back and forth over putting my extra JKU 44s in my ZJ. I would do the necessary upgrades to the front or go to the PR44 housing. The 30 spline shafts and 8.5" R&P have to be stronger than the 27 spline, 7.2" R&P of the hp30. I would be replacing a Ford 8.8 in the rear that would need alloys and c-clip eliminators. I know there won't be much strength difference in the rear with the Rubi 44, but the stance would be 5" wider, and bigger brakes than the ZJ has now. I can also swap the RCVs and Superiors from my Rubicon into these axles as the JKU will become a DD and toad behind the motorhome. I will be running 35s until they wear out (3 or 4 years) and then 37s. From what I'm hearing, I should also replace the rear locker with an ARB. Or is the 44 locker ok with 35s for now? Also I would run the 410 gears and go with a 4.3:1 Atlas vs. the 488s and 2.72:1 231 tc in the ZJ now. My thoughts are that the bigger pinion is stronger. Am I missing anything?

 

Are the 44s the same in the Xs and the Rubis, other than the diff?