When I stole my 1948 Willys pickup from the wife's cousin for a song some months ago, I started planning its buildup using some of the biggest, baddest parts around. But big and bad doesn't need to mean heavy and bulky.
The Rock Jock high-pinion...
The Rock Jock high-pinion centersection is cast of dense 206 T6 aluminum and angles the diff cover for high clearance. The DOM tubes are pressed into the centersection bores. Then the tubes are drilled and tapped for six bolts per side that pin them in place and keep them from spinning.
Enter the Currie Enterprises aluminum Rock Jock that's going under the front of this rig. Despite having 1 1/2-inch, 35-spline inner and outer 4340 alloy shafts, a Detroit Locker, 3-inch and 0.375 wall DOM axletubes, our front axle tickles the scales at a mere 344 pounds.
That includes the steering arms, spring pads, 1350 yoke, brakes, and everything else (minus the steering linkage). When you consider how strong the components are, the weight is insane. We visited the company's shop and looked over their shoulder as they assembled the front axle in a few hours.
With a WMS-WMS measurement of 70 inches, the axle looks like it belongs on a full-size more than a Jeep, but I'm building a low and wide wheeling monster, not a show queen. Tune in next issue to see what's going on in the rear.
Since you can't weld steel...
Since you can't weld steel to aluminum, Currie offers a bolt-on steel bracketry bridge to which suspension links can be mounted. However, since we're running leaf springs, Currie uses this steel collar that slips over the aluminum and is pinned on with the tube bolts. This is what we'll weld our spring perch to.
With the axle tubes securely...
With the axle tubes securely pressed and pinned to the centersection, the F-450 knuckles can be installed onto the tubes. John Currie set the caster to 6 degrees with a 4-degree pinion angle, then pressed the knuckles on. Each measurement is triple-checked before the housing is sent to the welding booth.
To ensure proper penetration...
To ensure proper penetration and a consistent bead, the housing is mounted onto a rotisserie jig that slowly spins it as the technician welds. Once the housing has cooled, it's thoroughly cleaned and brought over to the assembly area.
Putting junk components in...
Putting junk components in a housing like this would be like putting perfume on a pig. We ordered a set of Motive Gear 5.13 high-pinion gears (PN D60-513XF), a gear installation kit (PN D60IK), and a set of Warn Premium 35-spline hubs from Motive Gear, as well as a Detroit Locker from Detroit Locker (duh) so we wouldn't have to worry about component failures.
The axle uses 1-ton F-450...
The axle uses 1-ton F-450 unit bearings modified for a 5-on-5 1/2-inch bolt pattern. The 1 1/2-inch, 35-spline stub shafts are Currie's Performance 4340 chromoly units that we'll use genuine Dana Spicer forged 1480 U-joints in.
On the left is a stock Dana...
On the left is a stock Dana 60 front pinion bearing and on the left is the larger rear pinion bearing. One of the many advantages of the Currie Rock Jock centersection is that it uses the larger pinion bearings on both the front and rear of the pinion.
The Rock Jock also employs...
The Rock Jock also employs a removable skidplate made of 3/16-inch thick AR400 steel. It's the same super-hard stuff that are made from tractor buckets and bulldozer blades from. It's so hard it's nearly impossible to gouge, so it slides over rocks much easier than mild steel or cast iron.
When ordering a Rock Jock...
When ordering a Rock Jock front axle, you've got a choice between the standard F-450 steel knuckles (right) or Currie's cast aluminum knuckles (left). We opted for the aluminum units because they're strong enough for use with full-hydro steering (check out the extra material cast around the ball joints), but they also allow nearly any steering or brake configuration we could come up with.
With the 5.13s set up, the...
With the 5.13s set up, the LPW aluminum diff cover with carrier cap stabilizers was installed. The Currie Performance 4340 inner shafts were assembled to the stubs and were slid home, the hubs assembled, and the Wilwood rotors and calipers mounted. We'll show you more on the steering and brakes in a future issue.