As we’re writing this, the first freeze of the year is hitting the Carolina coast. By the time this hits the newsstands, it will be winter. If you live in a place that gets walloped with frigid conditions, you’ve probably learned to make the chilly season project-catch-up time. Over the course of each winter, we’ve spent countless cold nights in the garage with nothing but a small space heater and grand ambitions to keep us wrenching through the evening hours.
One of our more common winter-time installs would be to swap in a new-to-us (technically used most of the time) axle set. It’s with this memory of axle swapping in our pre-editor days that we can’t help but laugh at the fact that, over a decade later, we are at it again. This time, we’re in a much larger and nicer garage at Low Range 4x4 in Wilmington, North Carolina.
Last month, we went through our new G2 Axle & Gear Core 44 rear axle, and placed it under our ’99 Jeep Cherokee XJ. This month, we are hanging the matching JK-specific G2 Core 44 axlehousing up front. While two spring perches and a set of shock tabs made for an easy install out back, we knew there would be more fabrication involved to get the axle properly secured up front. For you Interweb aficionados, you may have researched a similar XJ-to-JK axle conversion.
Typically, the G2 Core 44 comes with 1⁄4-inch brackets already welded to the housing as it’s designed as a bolt-in upgrade for the ’07-current Jeep Wrangler JK. With our XJ’s mounting dimensions being different from that of the JK, we had our housing shipped bare.
If you believe everything you read on the web (why wouldn’t you?), you may have read that the JK axle is a simple “bolt-in” conversion. This isn’t entirely correct. Since we were aware of the challenges of installing a stock JK housing into an XJ, we had our G2 front axle sent the same as our rear, sans mounting brackets. This made it much easier for us to get everything placed exactly where it needed to be.
We still have a little ways to go, but we are making great strides towards the finish line. Be sure to check back next month as we give our steering a little assist and make appropriations for our 37-inch-tall Maxxis tires.
Step By Step
The one bracket that did come with the G2 housing was the upper control arm bushing. This setup actually bolts to the high-pinion American-made housing.
Two major weak links on the JK Dana 30 and Dana 44 front axlehousings are the thin-wall tubes and weak inner knuckle C’s. G2 takes care of those problems by adding massive forged inner C’s and using more durable 3-inch, 0.250-wall DOM tubing. New ball joints also come standard with the G2 axle.
We used a set of JK coil buckets, which placed the coil mount on top of the axle opposed to behind it as it does with the XJ perch. Going with the JK coil bucket allowed us to weld on this JK-to-XJ–specific track bar bracket from Synergy Manufacturing. The Synergy bracket offers three mounting holes to fine-tune your track bar placement and is designed to accept stock and aftermarket XJ track bars. It also has a place for a sway bar mounting tab.
Since the JK axle is a touch more than 5 inches wider than the XJ’s Dana 30, the coil buckets sit roughly 13⁄4 inch farther out on a stock JK axle. This is not an issue for us as there is plenty of space on the driver side of the axletube to move the bucket in.
On a JK, the lower control-arm mounts actually angle out. While we’ve seen some get away with keeping the stock lower brackets in place by using flex joints, it’s best to plan on removing them. It’s possible you could re-use the JK lower brackets and just swap them side to side, but since we were starting fresh, we welded a set of XJ-specific lower control arm brackets that we picked up from Rubicon Express.
We decided to use the G2 bolt-on diff-side upper bushing, which meant we needed to trim down the passenger side control arm mount that came with the RE kit. This evens up our upper control arm mounting points and fits both uppers with a durable rubber bushing.
For brute strength and terrain adaptability, we installed an ARB Air Locker. The legendary selectable locker uses forged spider gears that lock both axleshafts in unison when engaged. When not in use, the ARB Air Locker works as an open differential. This will help maneuverability both on-road and off-road, and prevent unnecessary wear and steering bind on our expensive frontend components.
Paired with our ARB Air Locker is a set of G2 Axle & Gear 5.13 gears. Since the G2 Core 44 uses the larger next-generation JK gears, we end up with a stronger setup versus a TJ Dana 44 front axle. The high-pinion diff also means we are sending power to the stronger drive side of the gear.
We were starting from scratch with the brakes as the G2 axle is designed to re-use existing JK outer components. We picked up our pads and rotors from Omix-ADA as the Jeep replacement parts company stocked almost everything we needed at a decent value. For the calipers and brackets, we called our local parts store.
G2’s Placer Gold front axleshafts bring the bling with the bright zinc finish. The 11⁄2-inch diameter ’shafts are heat-treated and forged from 4340 chromoly. While the standard 32-spline outers are designed to work with the JK’s unit bearings, the inside gets a step up to 35 splines to work with the RD157 ARB Air Locker. G2 provides beefy 1350-series Dana/Spicer U-joints to connect the Gold ’shafts together.
We assembled the outers with the bearings and steering knuckles we robbed off of our donor JK axle and connected it all using a Synergy Manufacturing tie rod bar. The 13⁄8-inch bar is made of 4130 chromoly and is double the strength of the stock tie rod. Given the width of the bar and low-mounting location on the axle, a stronger bar is a basic necessity on the JK. The Synergy bar is also swept at each end to clear the diff cover and sway bar tabs. Another handy feature is that it is fit with a double-adjuster sleeve, so we don’t have to remove the bar to set align the Jeep.
To make sure our steering geometry matched up with our track bar, we opted to run the draglink tie-rod end on top of the steering knuckle.
Doing so requires you to drill out the knuckle with a 7⁄8-inch drill bit and use a tapered insert, which we picked up from Synergy.
We sourced our tie-rod ends and tubing from Synergy and then built our custom draglink, which required a slight bend to clear the suspension components. While the Synergy track bar bracket is designed to work with a stock XJ front track bar, we decided to modify an adjustable Rubicon Express JK front track bar that Low Range 4x4 happened to have at the shop. We had to cut down the JK bar quite a bit to make it work. Working with an aftermarket TJ or XJ adjustable track bar might be easier if you have the option.
At the frame side of the Jeep, we used a reamer on the pitman arm to allow for the large tie-rod end from Synergy. The Rubicon Express track bar bracket and brace that was already attached worked just fine with the JK track bar, but we did have to drill out the Synergy axle bracket to accept the larger JK hardware.
We knew the 37-inch-tall Maxxis Trepador tires were going to be a tight fit with only 4 1⁄2 inches of lift, so we installed a set of extended Daystar bumpstops that pressed into the XJs original bumpstop mounts. These, in combination with our 2-inch-tall bumpstop pucks at the axle, should keep the axle in check. We’ll still have to trim, but the Daystar bumps will help tremendously.
The 4 1⁄2-inch Rubicon Express lift coils worked fine atop the JK coil buckets. We were even able to reuse the XJ’s aftermarket brake lines with the JK calipers as well. To dampen the suspension movement, Rubicon Express Monotube series shocks were bolted in.
The Rubicon Express control arms that were on the Jeep were bent and full of blown and worn joints. They lasted the previous owner five years of use and abuse, so we got a new set of the 0.250-wall chromoly arms. The 1310 yoke on the high-pinion axle allowed our stock XJ front driveshaft to bolt right up, but a quick inspection of the cardan joint showed it to be blown. We’ll address the drivelines, along with a few other issues, in next month’s installment.