Unleashing My Jeep: The Ultimate Willys EcoDiesel Build for the Rubicon Trail
Updated: Aug 28
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TL;DR / Quick Summary
Build vs. Buy: Instead of spending $90K on a new rig or $15K trading up to a used Rubicon, investing a $15K budget directly into a known, well-maintained 2020 Willys EcoDiesel creates a dedicated "Rubicon Killer."
Tires, Wheels & Drivetrain: Combining Black Rock Type 8 steel wheels with 35x10.5x17 Kenda Klever RT pizza cutters delivers high capability on a budget, paired with a professional Dana 44 re-gear to 4.10, Eaton electronic lockers, and chromoly/RCV axles.
DIY Front-End & Suspension: Upgrading factory components with Synergy heavy-duty ball joints and Metalcloak control arms provides bind-free articulation, proper caster angles, and reliable trail durability.Electronics & Tuning: Using an ECRI wireless calibration tool allows instant on-site speedometer, tire size, and axle ratio recalibration to maintain proper shift points and avoid limp mode on long highway drives.
What You Will Learn In This Post
Transforming a daily-driven 2020 Jeep Wrangler Willys EcoDiesel into a rock-crawling, overland-ready machine requires balancing high-end trail performance with a strict $15,000 budget. This guide breaks down the core reasons for upgrading a proven, familiar platform rather than purchasing a new Ineos Grenadier or factory Rubicon, ensuring you avoid inheriting someone else’s mechanical headaches while tailoring every bolt to your exact needs.
You will discover the exact hardware choices that make this build capable and durable, from pairing classic Black Rock Type 8 steel wheels with 35-inch narrow "pizza cutter" tires to bulletproofing the Dana 44 axles. We cover the split between DIY garage wrenching—such as installing Synergy HD ball joints and planning a flexible Metalcloak suspension setup—and trusting specialized pros like Premier West Gears for 4.10 gears, Eaton electronic lockers, and RCV axle shafts.
Finally, you will see how to handle the critical post-build electronics and calibration steps using the ECRI module to protect transmission shift points and prevent dashboard warning lights on long highway treks. Follow the complete build roadmap as this Willys evolves from local desert towing duties to running the iconic Rubicon Trail alongside our upcoming Jeep Jamboree adventures.
The Vision: Starting My Willys EcoDiesel Build
I decided to build a Rubicon-ready beast! What sparked this idea? Well, it was hard not to be inspired by those super cool and capable Jeeps and Grenadiers I saw at Overland Expo West. Plus, my buddy who tagged along kept raving about how much he loved my Jeep. It really shined when I towed my Xventure trailer to Alstrom Point on Lake Powell and cruised through the Grand Staircase Escalante.
Honestly, I wasn't too keen on dropping $90K on an Ineos, but I definitely wanted something beefier than my Willys. I played around with the idea of selling it and upgrading to a Rubicon, which would give me features like lockers, wider axles, and a sway bar disconnect. That would have set me back about $15K. In the end, I figured it made more sense to invest that $15K in upgrading my 2020 Wrangler's EcoDiesel instead.
997 Type 8 Steel Wheel Wrangler EcoD with a pile of new Steelies Kenda Klever & Black Rock Steelie Spare
The Look: Black Rock Steelies & Pizza Cutters
Would I liked to have bought some AEV or Method wheels? You bet but I have a love of steelies and this Willys Rubicon Killer Project has a limited 15K budget. The perfect compromise without compromising? Black Rock 997 Type 8 Steel Wheels made right in California USA. I paired them with a set of 5 Kenda Klever RTs sized 35X10.5X17 Pizza Cutters. Both are budget friendly but durable high performing choices.
Great Selection of Black Rock Steel Wheels Available on Amazon
Great Selection of Black Rock 997 Type 8 Wheels Available on eBay
Lessons Learned from the Gladiator Rubicon
This article and video is all about showing love to my Wrangler Willys Ecodiesel but I spent months in a knockdown-drag-out fight with death wobble on my wife’s Gladiator Rubicon. I won that battle—you can check the playlist in the card above. It’s ready for Moab in October, but that’s her rig. Out of respect, I only drive it from the passenger seat.
Build vs. Buy: Why I Chose the Willys Over a New Rig
The 2 vehicles pictured above got me thinking it was time for me to upgrade my dedicated off-road vehicle. When I mentioned to my buddy I was ready deal for a new Grenadier he kept reminding me what a cool rig my Wrangler Willys Ecodiesel is. When I got home I bounced around a lot of ideas about new rigs but everytime I jumped in the Willys it just felt right. I crunched the numbers and realized $15K in mods was a lot cheaper than $90K for new rig. That's when I developed my plan to transform my Willys Wrangler into Rubicon Killer. Once you factor in the purchase price, the potential unknowns, and the risk of inheriting someone else’s mechanical headaches? Forget it. My Willys has been babied for six years. I know every bolt on this thing.
DIY Mechanics and Professional Axle Upgrades
The OEM plastic lined ball joints definitely had to go. I bought some Synergy HD units. I knew it was going to take some DIY and help from professionals to get this rig modified right. I know when to DIY and when I should hand off a project, (usually.) Ball Joints I can handle, re-gear and lockers? I need the pros to assist.
Bulletproofing the Dana 44 M220 Rear & M210 Front Axle
Premiere West Gears, SoCal's best? I drove 700 miles each way to find out for myself. In the short lived run of Ecodiesels Jeep produced all were equipped with Rubicon Axles. The difference? Sport model Ecodiesels have the Narrow Track European style Rubicon Axles and the Rubicon models have the wide track Dana 44s. Those OEM Dana 44s are plenty strong but when you're building a Willys Rubicon Killer, axles are a key upgrade.
The Premiere West Parts List:
Dana Spicer REM Polished Ring and Pinion: Premiere recommended I go from the OEM 3.73 gears to 4.10.
Eaton Electronic Lockers: The OEM limited slip in the Willys is pretty good but no Rubicon conquering build would be complete without a sel to locking axles.
RCV Front Axle: Super strong axles with lock to lock turning ability. I'm intersted to see how these work out for me.
Revolution Rear Axles: Take a already strong Rubicon Axle and swap it out for Revolution units. That's a winner.
Avoid Limp Mode, Warning Lights, Sluggish Performance, and Bad Shift Points
Let me tell you about this ECRI Calibration Device—it's a game changer! After the crew at Premier West Gears finished re-gearing, installing my locker, and getting my axles sorted out, I had a 700-mile trek ahead of me from Southern California to New Mexico. I really wanted my Jeep to feel right on that long drive, and luckily, I remembered to bring my ECRI along for the ride.
What’s great about this device is how it works: you buy it once, pay per VIN, and then you can use it over and over again. So, once you’ve got it, it’s good for all your vehicles—and even your friends' rides too! Everything is handled through the ECRI App, including payment. I paid for my Wrangler the first time I changed tire size, and now I can recalibrate things like Axle Ratio anytime I need to. I actually did that right before I hit the road from Premier's shop. Super convenient!
Dialing in the Suspension: Metalcloak Upper Control Arms
You can't go wrong with MetalCloak and that is probably what I'll choose to replace the OEM suspension on the Willys Wrangler Ecodiesel Rubicon Killer Build. The photo above shows the parts I installed on the Gladiator. That build came out so good I can't really see any reason for going with any other parts. This phase is a way off so I'll keep an open mind to others manufacturers but at this point, MetalCloak is in the pole position.
Conclusion: The Roadmap: From the New Mexico Desert to the Rubicon
We have a trip to Moab with the Jeep Jamboree scheduled for late October and we'll be in the Gladiator with my wife behind the wheel. A fringe benefit of attending Jeep Jamboree events is you get on the advance list for the next years reservations. When it comes time to sign up for the next Jamboree I'll shoot for the Rubicon trip. By then I'll have the Wrangler Willys Rubicon Killer Build totally dialed in and we'll have a Rubicon capable rig. Of course, my wife will be behind the wheel for that one too.
I know along the way just like any project there are going to be surprises or what you might call Scope Creep. I'm sure I will find out I need more parts and mods than I bargained for. I'm just hoping I can stay close to that original $15K budget.
Muddy Ruttzz is a digital creator, overlander, and DIY enthusiast who documents rugged outdoor adventures and the gear that makes them possible through the Muddy Ruttzz brand. With a multi-decade background in industrial sheet metal fabrication, heavy infrastructure construction, and mechanical problem-solving, he brings a straightforward, hands-on trade perspective to technical builds, vehicle modifications, and digital workflow optimization.
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