Fans of the War Wagon, the Scorpion MK1, and this apocalypse-ready toy hauler might already be familiar with this Willys M38 (the military version of the civilian Jeep CJ-3A) built by Soni Honegger. It’s been called the “Slickrock Spider” for its remarkable ability to articulate its way over and through some of the hairiest obstacles known to four-wheel drive vehicles, especially with Soni at the helm. Let’s take a look at what makes this machine one of the greatest Flatfenders ever built.
Soni Honegger hails from Switzerland where even the smallest modifications to one’s vehicle, like aftermarket wheels, require approval from the government. When he lived in Arkansas, he decided that his wrecker and War Wagon were too large to navigate the tight and tree-lined local trails, so he built something more nimble.
He started with a 1948 Willys M38 and separated the body and frame. After many hours of meticulous consideration, and pushing the front axle forward five inches to get a wheelbase equal to that of a CJ-5, Soni had a coil-spring suspension that delivered maximum wheel travel.
Soni’s Willys M38 Rock Spider started with a 134ci flathead four-cylinder, BorgWarner T-90 transmission, and a Dana 18 transfer case. When we last checked up on the rig, it was powered by a 4.3-liter Chevy V-6 and crawled along with a granny-gear trans.
The differential gears under the Flatty were 5.38s and both axles were locked.
Where you’d normally find leaf springs under a Willys M38 flatfender, Soni devised a coil-spring suspension with radius arms that articulated in such a way as to earn the machine the name “Rock Spider.”
Soni’s M38 Rock Spider ran a set of the coveted 35-inch BFGoodrich Krawler tires (bring them back!) that seemed to hold onto rocks with adhesive properties.
When other vehicles became immobilized on the trail, the hydraulic winch on the M38 Rock Spider was always ready to lend a tug.
Locals in northern New Mexico have been known to see this rig on the road. At some point, Soni’s Rock Spider sported a rollcage, but we’ve also seen evidence of him singlehandedly (and we do not condone this ever) stopping a rollover incident with an outstretched arm (again, never do this, and keep all limbs within your vehicle, always).
Would you consider trading leaf springs for radius arms in your rockcrawler?
Droop is key to making the Rock Spider as flexible as it can be.
The interior was spartan yet functional.
Below these switches actuating the front and rear lockers you can see the shift pattern etched into the paint.
Read about Soni’s War Wagon, his epic 1980 AM General M920 toy hauler, and the Scorpion build by clicking the links!
Watch: Four Wheeler’s Verne Simons Plugs a Tire on an Old Jeep
Keyword: The Rock Spider Is a Link-and-Coil-Sprung Flatty That Can Out-Crawl Your Jeep