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Bent Rubicon D44 Solution: G2’s CORE 44

Posted in How To: Transmission Drivetrain on February 21, 2017
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The JK Wrangler has arguably become the most-popular Jeep in all the iconic 4x4 brand’s history and the addition of the four-door Unlimited filled a gap that needed to be filled. With the higher sales numbers comes more breakage. JKs are typically put under more stress, mostly because of their overall size and the wheelwell openings. Those giant holes are great for stuffing 35s, 37s, and bigger under the Jeep.

Stock, a non-Rubicon JK comes with a Dana 30 up front. Rubicon models step up to a Dana 44 front as well as selectable lockers front and rear. The internal components of the Dana 44 are strong, typically the weak link is the housing. Bent tubes, broken castings and mangled bracketry are common failures. That’s where G2 Axle & Gear has jumped in with their CORE 44 housing.

The long side of a differential housing is the most likely to bend due to leverage and physics. The Rubicon Dana 44 seen here was bent back towards the rear of the vehicle, as well as up.

The G2 CORE 44 is a beast compared to the stock Dana 44. The tube size is bumped up to 3 inches in diameter with 5/16-inch wall thickness. All bracketry is laser cut and CNC formed from 1/4-inch steel and comes prewelded for direct installation. It can use the same 8.5-inch Rubicon Dana 44 ring-and-pinion set, the same factory Rubicon selectable locker, and bolts right in as a replacement. G2 also sells the CORE 44 with internals preinstalled and ready to go. Choose between an Auburn ECTED, ARB Air Locker, Eaton E-Locker, or the G2 selectable locker. Gear choices from 4.10 to 5.38 are available. Additionally, the CORE 44 features a unique G-lock adjuster nut system. The adjuster system allows installers to quickly and accurately set backlash without having to remove carrier bearings and replace shims.

Of course, there are other options out there if you have a bent Dana 44 housing. Upgrades to Dana 60s in various forms (junkyard swaps and the like), but keep in mind there are plenty of ways to keep your differential from bending in the first place. Careful driving is probably the biggest way to avoid it. Try not to jump the vehicle or otherwise land hard. However, there are times when higher stress is unavoidable. EVO Manufacturing, Artec Industries, and G2 all make laser-cut truss systems that are designed to drop directly onto the stock differentials and weld on. A truss system will reinforce the tubes and casting to help strengthen the housing.

When one thing bends, it is likely something else bent as well. The upper control arm mounts on JKs are significantly stronger than previous generations, but it was still no match for a well-rooted tree stump.

Follow the straightforward install of a CORE 44 bare housing into a ’16 JK Wrangler Rubicon that was brought into Dependable Offroad in Anaheim, California, because it had an unfortunate meeting with a large and well-rooted stump.

Side By Side Comparison

Both the stock Dana 30 and Dana 44 housings have the same material dimensions. This is how they stack up against a CORE 44:
Tube Diameter
CORE 44: 3-inch
Stock: 2.5-inch
Tube Wall Thickness
CORE 44: 0.3125-inch
Stock: 0.250-inch
Inner C (ball joint mount)
CORE 44: Forged steel
Stock: Cast steel
Bracket Material Thickness
CORE 44: 0.250-inch
Stock: 0.1875-inch
Bearing Caps
CORE 44: Forged steel
Stock: Cast steel
Additional:
CORE 44 has extra ribbing and gussets to reinforce weak points.
CORE 44 Uses G2’s “G-lock” Adjuster nut system for ease of install and more precise bearing setup.
CORE 44 is available with two different bracket arrangements for proper caster: 0 to 4-inch and 4-inch plus.
CORE 44 is available as an empty “bare” housing or fully assembled with your choice of locker, gear ratio, and axleshafts.
CORE 44 is also available as a direct replacement for non-Rubicon JKs, as well as TJs and YJs.

During impact, the tree stump left a little reminder for the vehicle owner. Both tire and wheel were no longer usable.
It’s always a good idea to lay out your parts before you take anything apart. Better to find you’re missing something or have the wrong parts before you have disabled your vehicle. G2 has now put together a single part number for each available ratio to get front and rear ring-and-pinion sets as well as bearings.
Disassembly is relatively easy, just make sure to be careful with the wires for the factory electric locker. They can be easily damaged if you are not giving them any attention.
Clean up the factory locker assembly and install the new ring gear. When reinstalling the locker actuator, make sure it is lined up properly for installation into the new G2 CORE 44.
The pinion is installed using a modified bearing that slips on. Using an install bearing allows the bearing to be easily removed when shims need to be changed multiple times to find the right pattern. Once the pinion is in place, install the locker and ring gear assembly for initial setup. This takes a fair amount of dexterity and maybe even an extra hand or two due to the adjusters of the G-lock system. Make sure to keep the wires of the actuator pointing out so they do not get bound or damaged.
The G2 G-lock system makes fine tuning the backlash a breeze. With the bearing caps snugged, a screwdriver is used to adjust the positioning. A mechanic with plenty of gear setup experience will be able to adjust the system by feel and get it very close for initial testing.
The pattern is checked using yellow grease paint. The marks show exactly how the gears are meshing together and which way things need to be moved for optimal engagement.
The locker assembly and ring gear are then removed so the pinion shims can either be adjusted or locked in with a final pressed-on bearing. Then install the engagement sensor. The pin of the sensor blocks the pinion, forcing it to be removed so the pinion can be removed.
Reinstall the locker, check final pattern adjustment, and lock down the actuator using the original factory bracket. During this install, the bracket did not conform very well to the new bearing cap it rides over. The material it is built from is thin enough, however, to allow it to bend as needed and keep the actuator from spinning with the carrier.
The technician opted to install the internals after the new CORE 44 housing had been hung off the control arms of the Jeep. The housing bolts in just as the factory unit did, using all the same hardware and mounting points.
The original steering knuckles bolt onto the new ball joints and the original axleshafts slide in. The CORE 44 truly is a bolt-in differential replacement.
Some of the biggest strength benefits of the CORE 44 is the extra ribbing in the casting. The unit can take much higher stress levels than the factory unit because weak points have been identified and rectified.
A broken inner-C is rare compared to a bent axletube, but it is still a weak point. G2 wanted to resolve any potential issues beforehand so the inner-C casting of the CORE 44 was significantly beefed up.

Sources

G2 Axle & Gear
Compton, CA 90220
310-900-2687
www.g2axle.com

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