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We Swap Currie RockJock 44 Axles Under A Jeep XJ Cherokee

Posted in How To: Suspension Brakes on October 13, 2017
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We recently showed you, step-by-step, how front and rear Currie RockJock 44 axles were built, and more specifically, how they were built to bolt right up underneath a Jeep XJ Cherokee. The details of construction as well as why these custom Currie RockJock axles are extra beefy were also brought to light. Now comes the next step. We will take you through the process, again in a step-by-step manner, of installing these massive logs and hooking up the Eaton ELockers inside them underneath a 1995 Jeep XJ Cherokee.

First, let’s start with a little prep. Before we could begin the installation of the Currie RockJock 44s, we had to remove the factory axles. This entailed unbolting the factory steering system from the box down. Aside from the necessary, but standard-issue wrenches and sockets, a pickle-fork, and a hammer came in handy to separate the ball joints from their mounts on the frontend. Brake caliper sets were removed from the front axle—but left connected to their brake lines—and simply hung out of the way on the unitbody “frame rails” with wire. Because the rear axle came with disc brakes to replace the drums of the factory rearend, the rear brake hose had to be disconnected and clamped off with vice grips to keep brake fluid from running out like Niagara Falls. The Currie RockJock 44 rear axle did not come with a threaded post to secure a T-block fitting for the rear brake fluid lines, so we welded one to the driver side tube of the new rear axle.

We worked with 4West in Colton, California, for this axle swap. 4West has been in business under the same ownership for four decades, and is a top-shelf and experienced retailer and installation facility, with a team that lives the Jeep lifestyle. Although this installation could be done in your home garage with the right tools, having access to the 4West shop cut our installation time in half. We were in and out in a day, and drove home with Eaton ELocker-filled Currie RockJock 44s under both ends of our ’95 Jeep XJ Cherokee. Follow along to see how you can do it too.

Working with the experienced team at 4West in Colton, California, made this installation a lot easier, but even without things like two-post lifts, air tools, trans jacks, and axle racks, this job can be done in your own garage. Once the OE rear axle of our ’95 Jeep XJ Cherokee was removed, the new Currie RockJock 44 was lifted into place, so that the holes in the RockJock’s spring pads could be aligned with the pegs underneath the center of the spring packs.

Due to the substantially larger tube size of the Currie RockJock 44 in comparison to that of the OE axle (Chrysler 8.25-inch, C-clip, 27-spline axleshafts), we needed larger (3/16x 3 x 7 1/2-inch) U-bolts. Tip: We were able to scavenge and reuse the factory spring plates. However, the holes in the spring plates did have to be drilled out to accept the larger new 3/16-inch U-bolts.

Once the U-bolts and springs pads were fastened together and holding the Currie RockJock 44 rear axle securely to the rear leaf springs, the shocks could be bolted up to the lower shock mounts on the axle.

Because the Currie RockJock 44 rear axle came without a threaded post for the T-block rear brake fitting, we had to weld one into place atop the driver-side tube of the rear axle.

Our Currie RockJock 44 rearend came with new Ford Explorer 11-inch disc brakes, so the OE parking brake cables would not have done the trick. The old parking brake cables were replaced by a new set of parking brake cables (PN 4304171) from TeraFlex specifically designed for this application.

A completely new hardline brake-fluid tube system had to be plumbed on to the Currie RockJock 44 rear axle. This is where the proper tool makes a job so much easier. A handheld tube bender was used to precisely form the brake line system for the rear axle.

A T-block for the rear brake fluid system was bolted to the threaded post we welded on to the Currie RockJock 44 rear axle. Both sides of the hand-fabricated hardline brake fluid tube system were plumbed in, as was the braided steel flexible line bringing brake fluid from the master cylinder.

The breather tube was hooked up to the new rear axle, and the signal wires coming from the ELocker inside the Currie RockJock 44 rearend were attached to the wiring harness supplied by Eaton. The breather tube and wiring harness were then zip-tied together and strung up and secured to the underside of the body, making sure enough slack was left to account for axle articulation. From there, the wiring harness was routed along the inside of driver-side unitbody “frame rail” to the engine compartment.

With the rear axle installation nearly complete, we moved forward to the begin getting the front Currie RockJock 44 lifted into place. Again, this job was made much easier due to the trans jack and axle rack the 4West team had on hand, but this is a job that can be accomplished by the DIYer.

The two lower front control arms (our ’95 Jeep XJ Cherokee had been previously upgraded with a 4 1/2-inch suspension kit, which included replacement lower and upper control arms) were bolted into place on the lower control arm brackets of the Currie RockRock 44 front axle. Tip: It’s a good idea to leave all the bolts on the frontend tight but not fully torqued (especially if you have replaced the rubber bushings with polyurethane), as it’s easier to get everything, including the steering system, to fit if it’s all a little loose until installation is complete.

We secured the two upper front control arms to the upper control arm brackets on the Currie RockJock 44 front axle. The new axle’s upper control arm bracket eyelets featured Johnny Joints, which are superior in their articulation capabilities and strength and allow for excellent lubrication through their built-in greaseable fittings.

With the XJ on a two-post lift at 4West, we were able to easily lower the front axle to make getting the coils (also part of a previously installed 4 1/2-inch suspension lift) and their top spacer bushings and lower bumpstops back into position. The DIY mechanic may have to use a jack to lift the vehicle in order to create room between it and the new axle to achieve the same result.

Once the coils were back in place, we bolted new TeraFlex (PN 1910234) TJ lower bump stops (these were solid polyurethane, as opposed to the old honeycombed units) that inhabit the interior of the springs to the spring pads on the new front axle. Although meant for a Jeep TJ Wrangler with a 3- to 4-inch lift, they worked perfectly on the XJ due to its similar front suspension design and preexisting 4 1/2-inch suspension lift. The bump stops have countersunk holes in their centers so that the heads of the bolts don’t become rigid bump stops.

At this point, we reattached the bottoms of the front shocks to the shock mounts on the Currie RockJock 44 rear axle. Hardware from the preexisting front axle (Dana 30, high-pinion, reverse cut, 27-spline axleshafts) was reused for this job.

The ball-end lower mounting hardware for the quick-disconnect anti-sway bar end-links was salvaged from the old Dana 30 front axle and they both were bolted back into place on the Currie RockJock 44 front axle.

We also salvaged the steering knuckles from the old Dana 30 front axle to use on the new Currie RockJock 44 frontend.

The Currie front axleshafts were carefully reinstalled into the RockJock 44 front axle. They were removed to allow the installation of the salvaged steering knuckles from the OE Dana 30 front axle.

The OE front backing plates and front hub assemblies were salvaged from the Dana 30 front axle and reinstalled on the OE steering knuckles. Three bolts secure the backing plate and hub assembly to each steering knuckle. A single large gland nut and cotter pin locks the hub assembly to the end of each axleshaft.

The OE disc brake “hats” were slid back onto the hub assemblies, and the OE front disc brake calipers, which had remained connected to the brake lines and temporarily hung from the unitbody “frame rails,” were reinstalled on the steering knuckles. Be careful to not lose (replace them if they’re worn) the small metal clips that ride between the upper caliper mounts on the steering knuckles and the brake calipers. If these clips are not replaced, the calipers will vibrate and chatter during braking.

A small come-along came in handy to help “align” everything when we attached the reused track bar (part of the preexisting 4 1/2-inch lift suspension kit) to its locating mount on the new Currie RockJock 44 front axle.

We tossed the old OE steering linkage system for a much better and sturdier Currie Currectlync Heavy Duty Steering System (PN CE-9701). The installation was quick and easy. We measured the old steering link lengths and began with the same lengths on the adjustable Currectlync steering set up, with final measurements and adjustments to be made once the tires were on and the rig was back down on the ground to set proper toe-in. The quick-disconnect anti-sway bar end-links were reconnected at this time. A brand-new Fox (PN 985-24-072) Steering Stabilizer was bolted up to help give a much needed calming effect with the new 35x12.50R17LT Toyo Open Country R/T tires on 17x9-inch KMC 126 Enduro Pro wheels. We had to go to 17-inch wheels to clear the new disc brakes on the Currie RockJock 44 rear axle.

Both of the new Currie RockJock 44s had been connected to their respective breather tubes and the front and rear Eaton ELockers wired to their harnesses. At this point, we filled the new front and rear axles with Torco “9+” SAE 85W/140 Racing Gear Oil. Currie recommends the front high-pinion RockJock 44 receive 1-1/2 quarts and the rear low-pinion RockJock 44 get 2 quarts. The new axles feature threaded fluid-fill plugs with dipsticks. To accommodate periodic fluid level maintenance, we installed the dipsticks finger tight, then removed them and scribed a mark on the dipsticks where the fluid levels were, then reinstalled and tightened to 20 foot-pounds.

Once the Jeep XJ Cherokee was back on the ground with all four tires bolted back up to the ends of its new Currie RockJock 44 axles, toe-in was preliminarily set the good old fashioned way–by measuring the front and rear distances between the tires and making the appropriate adjustments. We always recommend a full professional alignment after any chassis upgrade, but this down-and-dirty alignment got the rig back home safely. The entire vehicle was then gone over to finalize the proper tightening of all hardware. The rear brakes were then bled because, unlike the front calipers, the OE rear drum brakes had been disconnected and replaced by the discs on the new rear axle.

The wiring harnesses leading from both axles were loomed through to the engine compartment. The relays were attached to the firewall next to the master cylinder with sheetmetal screws. The harnesses’ power wires (which contain 10 amp fuses inline between battery and relay) were strung to a key-on power location, as well as along the firewall and then forward to the battery across the passenger side inner fender well. The control wires were run through a preexisting hole in the firewall and under the dash to a switch panel. Eaton-kit supplied lighted rocker switches control the signal to the ELockers.

We used a switch plate from Prime 4x4 that comes ready to mount the Eaton ELocker switches. The plate screwed on using hex-head button hardware and covered the “change pocket” in the forward end of the XJ’s floor console. A hole just large enough to feed the wires through was all that had to be cut. There is enough room between the switch plate and the change pocket to allow for the depth of the switches. The Prime 4x4 switch plate came with five slots. We covered three with black tape to keep dirt out until more accessory switches can be moved to this new plate.

The last but certainly not least important step in the installation of the new Currie RockJock 44 axles underneath the ’95 Jeep XJ Cherokee was to alter the proportioning of the brake system to account for the change from drums to discs in the rear. Here’s how we did it. By holding the proportioning valve steady with a crescent wrench and unscrewing the front bleeder cap with an open box wrench, we accessed the bleeder valve piston. After removing the bleeder valve piston, we removed the O-ring, and then replaced the piston, spring, and bleeder valve cap. By removing the O-ring from the piston, we effectively changed the proportioning ratio of the brake system to send more fluid and pressure to the disc brakes. It did the trick, and the rig’s brake performance was much more balanced and effective overall. Tip: Have lots of rags positioned underneath the valve during this operation. Brake fluid will eat paint and plenty of other things it gets spilled on. You will need to top off your brake fluid reservoir afterwards, too.

Sources

Currie Enterprises
Corona, CA 92880
714-528-6957
http://www.currieenterprises.com
KMC Wheels
Cerritos, CA 90703
877-943-3577
www.kmcwheels.com
Eaton
Cleveland, OH 44114
800-386-1911
http://www.eaton.com
Toyo Tires
800-442-8696
www.toyotires.com
TeraFlex
801-713-3314
teraflex.com
Fox
800-369-7469
http://www.ridefox.com
4West
909-824-0024
4west.com
Prime 4x4
801-835-6215
prime4x4.com

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