Most of what I have read about the 'Next Generation' axles found on the JK's is about the Dana 44's. Yet, I still have a couple axle questions about both the new D44 and D30, just so I am totally clear on these axle differences.

I understand that the X/Sahara rear Dana D44's have a smaller spline count than the Rubi D44's; 30 vs 32. Is the shaft size the same, just more splines? Other than spline count and the electronic locker in the Rubi, are the Dana 44's found in both the Rubi and non Rubi JKs the same?

It is also my understanding that the new D44s have a larger R&P and thicker tubes than the TJ D44's. Correct?

I also understand that the Next Generation Dana 30 front axle is a high pinion as opposed to earlier TJ D30's. Is the new D30 any beefier than the TJ D30 front? Axle size? Spline count? U joint size? Tube thickness?


Thanks for any help!

 

The JK D30 and D44 use basically the same housing, with the exception of the center section in the 44 being larger to fit the 44 gears. Same length and tube size and thickness.

They are 5" wider than previous axles, and have taller C's, so they are proving to be more prone to bending. There is also some suspect metallurgy going on, and we are seeing a lot of these housings shatter.

X/Sahara/Sport
D30 front - 32sp outer / 27sp inner
D35 rear - (some early 07's. Haven't seen any spline info)
D44 rear - 30 sp

Rubi
D44 front - 32sp outer / 30sp inner
D44 rear - 32sp

Both front axles use the same outer shafts, rotors, brakes.
The ujoints on the 44 front are larger. Both are high pinion.
All JK gears are thicker than previous gears, and the 44's are a bit larger in diameter also. (not sure about the 30's)
The 32sp rubi rear axles are larger diameter than the 30sp non-rubis, and they are also different lengths than the non-rubi rear shafts.
Rubi diffs are an oddball size, the only non-rubi locker that will fit is the 35sp ARB, and to use it, you have to run 35sp shafts.
The D30 and non-rubi D44 can use any standard diff/locker.

 

Is this happening in stock and close to stock jeeps or usually only in heavily modded JKs being wheeled hard?

Thanks!

 

Good info! Subscribed

 

Stock, 32's, street driving. Ran up onto a sidewalk at 20mph. How is that for "Trail Rated!"
https://www.jk-forum.com/forums/show...on-please-help!!!!

If you look through WOL's big 'check your front housings' thread, you will see one with inner sleeves that shattered. The sleeves simply moved the break point to the end of the sleeve at the diff...


Honestly, in the grand scheme of things, the number of shattered housings is very low. But it's a roll of the dice as to whether or not you are one of the lucky ones.

 

Thanks for the advice, nthinuf!