A custom axle for Anthony's TJ

Hickey

Rusty Girdle
Supporting Member
Most of you are aware that @SoopaHick Anthony is my son and he bought Carl's old TJ. Some of you might be aware that he has been having problems with his from axle. This thread is to document the build of a custom axle to replace his dying Dana 30.

Some time last summer Anthony started hearing a ticking noise. Long story short, his ARB was coming apart. After some research we learned that the early ARB design for the Dana 30 was problematic. The housing flexes too much and the lockers case bolts back out. Trussing the axle does not fix the issue, and ARB has since redesigned their locker to fix the problem.
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We put new case bolts in and welded the damaged cross shafts in place.

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Hickey

Rusty Girdle
Supporting Member
We knew from our research that the repair was only temporary and the case bolts would happen again, so we began sourcing a replacement. We didn't want to keep polishing a turd. We were able to pick up a damaged Tera 44 for a JK Rubicon for a great price and decided that would be nice our starting point.

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This picture shows a stock JK/TJ axle tube slid inside the Tera 44 tube. This is the major strength gain with the Tera 44 axle over a stock axle.

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As you can see, the driver's side inner C needed to be replaced, and we decided to narrow the axle to TJ width while we were at it. Being a street legal Jeep is important for this build.

We cut off the old C's and coil buckets as well as 2.5" of tube length on each side.

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We sourced another inner C from Currie and prepared both C's for install by using the gas grill to heat the knuckles up so they would expand slightly.

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Grab TWO pairs of welding gloves and pick that 500 degree knuckle up and run to the garage and slide it into the tube. You may need to coax it on there with a BFH.

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We set the pinion flange at 6 degrees high and welded the housing to the fab table. We then use an angle finder to ensure the C's went onto the tube at the correct caster of 0 degrees. When the axle is installed, the pinion flange will be 90 degrees to the ground and the inner C's will have 6 degrees.

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C's welded in place.

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Hickey

Rusty Girdle
Supporting Member
The coil buckets will be moved in a total of 1.75" on each side to match the TJ locations. They will also be centered on the axle tube like on a JK axle, instead of being mounted forward of the axle centerline like a TJ/YJ/XJ axle. This will move the axle forward almost 2".
 

I Lean

Mbryson's hairdresser
Supporting Vendor
Location
Utah
What's the factory pinion angle on the JK axle? (or the relationship between the knuckles and the pinion)
 

Hickey

Rusty Girdle
Supporting Member
Looks like 1 degree up, but that's with only 5.3 degrees caster. That wasn't enough caster for my 2 door jk. Anthonys should do pretty well as we are going from a low pinion axle to a high pinion, so his driveshaft angle will be pretty shallow.
 

Hickey

Rusty Girdle
Supporting Member
So you set it up essentially the same as the 0-3" JK housing. Cool.
I was also able to salvage the Tera coil mounts, which is great because they are really nice fabricated mounts. The coil mounts on my Tera44 in my JK are stamped, and they just don't look as nice as these do. I think the track bar will work out just about perfect, just need to extend it a couple inches.
 

Omgbecki

Well-Known Member
Location
Ogden
That's a pretty good read. Definitely past anything I could take on but really informative.
 

SoopaHick

Needs More Money
Location
Provo, Utah
Subscribed. Looks like a great upgrade.
I'm excited for it. Seeing that Tera44 compared to the TJ Dana 30 it's almost laughable.
 
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SoopaHick

Needs More Money
Location
Provo, Utah
Did you cut it down to use off the shelf shafts from a TJ Rubicon? Or will you have custom shafts?
No we cut it down to make it legal under a TJ, if we left it JK width the tires would stick out 3ish inches past my fenders on each side and I'm already stretching my luck with my current tire stickout and no mudflaps.. Plus it would be obviously wider than my rear axle. We'll be doing custom shafts.
 

I Lean

Mbryson's hairdresser
Supporting Vendor
Location
Utah
No we cut it down to make it legal under a TJ, if we left it JK width the tires would stick out 3ish inches past my fenders on each side and I'm already stretching my luck with my current tire stickout and no mudflaps.. Plus it would be obviously wider than my rear axle. We'll be doing custom shafts.
A TJ Rubicon would have the same width axle as your stock 30, just in 44 flavor.
 

Hickey

Rusty Girdle
Supporting Member
Did you cut it down to use off the shelf shafts from a TJ Rubicon? Or will you have custom shafts?
Custom shafts. I originally thought that using the TJ Rubicon shafts would be an easy route. There are two problems with that. JK Rubicon shafts use a larger/stronger Ujoint and outer stub shaft than the TJ Rubicon, and the JK Rubicon locker's spider gears are offset in the carrier.

There is a company offering TJ Rubicon shafts with the larger JK Rubicon joint in them, but we would have to cut unequal lengths off of this axle's tubes, and that would mean moving all of the control arm mounts about 1".
 
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