Showing up for a job interview hung over or driving at breakneck speed off-road in a lifted JK Wrangler can produce predictable results, none of which is favorable. And while we may not be able to change your drinking habits, we can tell you how to keep your late-model Jeep's front axle from smiling under stress.
With 35-inch-plus tires and only moderate wheeling, the factory '07-'10 Wrangler front axlehousings are known to bend, even on the Rubicon model. There are several weld-in aftermarket kits available to sleeve the inside of the front axletube for more strength, but the increase is only marginal and no amount of weld-on gussets can straighten an already-bent axlehousing. Thankfully, Dynatrac came up with a beefier solution that has other added benefits, including more ground clearance than stock. It didn't take us long to load up our '07 two-door Rubicon and hit the Dynatrac shop for the full scoop on this U.S.-designed-and-built solution.
The JK ProRock 44 comes complete...
The JK ProRock 44 comes complete with new upper control arm bushings, ball joints, inner axle seals, and a heavy-duty Dynatrac diff cover. Options include ProSteer heavy-duty rebuildable ball joints and control arm skidplates.
The stock JK front axles feature...
The stock JK front axles feature axletubes made from 2.50-inch-diameter, 0.250-wall tubing (left). The Dynatrac ProRock 44 features massive 3-inch diameter tubes with 0.3125-wall tubing for over double the strength over stock (213 percent). Most inserted tube gussets provide only a 30-percent increase in strength over stock.
The overlay of the ProRock...
The overlay of the ProRock 44 (blue) on the stock JK Dana 44 (green) illustrates the increased ground clearance. Combine the added clearance with the beefy Dynatrac differential cover and you've got a pretty lethal trail combo.
There's more to it than just...
There's more to it than just adding heavier tubes or gussets to the axle assembly. The ProRock 44 centersection has a higher gross axle weight rating than the stock JK centersection. The Dynatrac centersection is thicker everywhere and features more reinforcing ribs than the original JK housing.
Dynatrac even redesigned the...
Dynatrac even redesigned the end forgings for more strength. The factory JK end forging (left) is dwarfed by the ProRock 44 piece (right). This added material prevents bends in the knuckles, yet still allows use of the factory JK ball joints and other components.
We got less than 50,000 miles...
We got less than 50,000 miles out our stock JK lower ball joints before they got wobbly. The optional heavy-duty Dynatrac ProSteer ball joints should be available by the time you read this. They feature stainless steel internals and are completely rebuildable at home or even on the trail.
All of your Rubicon JK Dana...
All of your Rubicon JK Dana 44 internals, including the electric locker, factory or aftermarket ring and pinion, sensors, bearings, axleshafts, and so on, bolt right into the ProRock 44. You can also opt for a ProRock 44 housing machined to accept other lockers (ARB, Detroit, etc.). However, this option requires the use of custom inner axleshafts.
Your original JK knuckles,...
Your original JK knuckles, axleshafts, unit bearings, and brakes all bolt on to the ProRock 44. Even our aftermarket RCV Performance axleshafts fit like a glove in the new Dynatrac housing. Don't forget to smear anti-seize on the stub shaft splines, unit bearing mating surfaces, and unit bearing mounting bolts.
The ProRock 44 specs are nearly...
The ProRock 44 specs are nearly identical to stock, so most installations do not require gear setup or special installation tools. However, it's still a good idea to check the backlash and gear pattern before disassembly of the old housing and match it up once everything is reassembled in the ProRock 44. Make any needed shim adjustments and always install a new crush sleeve to set proper pinion bearing preload.
All of the brackets on the...
All of the brackets on the ProRock 44 are twice as thick or thicker as stock to reduce the chance of bending when they hit trail obstacles. Each one, including the heavy-duty reinforced track bar bracket (pictured), is fully-welded to the massive housing tubes to ensure that they will not tear off.
We've put our '07 Rubicon Wrangler through 58,000 miles of on- and off-road use and abuse over the last three years. About 20,000 miles of that was rolling on 35-inch tires. The steering wheel had a bit of a shimmy when we took the Jeep over rough paved roads. We set the toe out 1/8-inch and that helped correct the problem, but a slight wobble persisted. Our housing wasn't as bent as others we've seen, but the bend was still visible with the naked eye. It turned out that our lower ball joints were shot as well. On top of that, several months ago our factory Rubicon locker had problems unlocking and we never could figure out exactly why. So we had unlocked it manually and unplugged the electrical connections. When Dynatrac pulled the gears and carrier from our original axlehousing, there was almost no preload on the carrier bearings. This could have been caused by wear from contaminated oil, but since the bearings didn't look overly-worn, it is more likely it was the result of a bent housing and centersection. Dynatrac replaced all of the bearings in our axle along with the electric locker solenoid during the assembly of our ProRock 44. We slapped the axle back in the Jeep ourselves, and can honestly say that this is one of the few bolt-in parts we've installed lately that actually bolted in with no grinding, drilling, cutting, or welding. We had to reset the toe-in and recenter the steering wheel after the installation, but it's a simple at-home procedure made easier with a buddy and a tape measure. Now our locker works, the shimmy over rough roads is gone, our housing looks straight, and it's not likely to bend again.