Editor’s note: This article was originally posted in Overland Journal’s Spring 2021 Issue.
Traditionally, the best SUV platforms in North America have been restricted to the Land Cruiser offerings, and to a lesser extent, the 4Runner, G-Wagen, and Land Rover wagons. In 2003, Lexus released the GX model in North America, Russia, and other limited markets based on the international J120 chassis. What was critical was its association with the “J” designation, which shares the general emphasis on robustness and reliability of the Land Cruiser. In numerous markets, the J120 is even called a Land Cruiser or Prado. Development began in the late 1990s with Lance Scott of Toyota ED (Europe), which is often considered the pinnacle of the body-on-frame era, and the J120 possesses a long list of desirable traits. Most notable are the high-strength frame construction, five-link solid rear axle design, and the coilover independent front. The J120 has won numerous awards throughout the globe, including winning Fourwheeler of the Year. In addition to the above accolades, the Lexus variant received the venerated 4.7-liter V8, known to be one of the most reliable engines ever sold in the USA. The GX is made in Tahara, Japan, on the same production line as the international Prado and 4Runner.
WHY A GX 470?
We wanted to build a platform that struck an ideal balance between reliability, performance, and value, contrasting some of the eccentricities of our decade-long G-Wagen build. The G-Class was a wonderful vehicle, and I could have easily driven it for another decade, but it had limited appeal to our audience—it was time to try something new. As a result, we purchased a clean 2007 GX 470 in Arizona in the spring of 2018, where it served daily driving duties and remained unmodified for over a year. The delay in modification yielded numerous benefits, including learning the stock platform’s limitations and how it genuinely needed to be improved. This article will focus on all of the off-highway modifications, recovery solutions, and electronics employed to prepare the GX for remote backcountry travel.
With so many options on the market, my search kept bringing me back to the GX, as it was a better value than the 4Runner, and had a higher payload than anything in the decision set short of a 200-Series Land Cruiser. The payload rating is due in part to the 7-passenger seating, but also because of the airbags with automatic load leveling. In some markets, the payload of the J120 ranged as high as 1,907 pounds, which inspired confidence in the reserve capacity of the GX (although GVWR was not exceeded). The ride and drive of the GX on the road significantly improves comfort and makes the long pavement stretches easier on the occupants. Despite our love of the backcountry, most trips require an investment in highway miles to reach the trailhead. For off-highway performance, the GX is impressive even in stock form, only limited by ground clearance at the rear bumper and along the running boards. The 109-inch wheelbase makes the vehicle a good balance between stability and maneuverability on the trails. And of important consideration, it is possible to buy a clean GX 470 with reasonable miles for as little as $17,000.
ESTABLISHING A BASELINE
In that first year, it became evident that a few things needed to be addressed before modifications began. For this, I called DeYoung European Motors, the same outfit I trusted for 10 years with my G320. Most noticeable was the ailing rack-and-pinion steering, which is an area of weakness for the platform. The rack, bushing, and pump were all showing signs of wear, including aleaking pressure line. With larger tires in the plan, we rebuilt the system with all-new parts and strengthened the tie-rod ends with their Tie Bo No stainless steel reinforcement rods.
Additionally, any lift put added strain on the CV axles due to the change in the operating angle. The original CVs showed signs of wear and were leaking grease from the boots. While the front end was being freshened, the CV axles were replaced with factory Toyota parts to ensure long service life and strength on a lifted AWD SUV.
There were a few functionality items I did not care for on the GX, mostly related to the undermounted spare, the factory side steps, and the limited underbody protection. Given that the GX is based on the Prado, it has a swing-out rear gate, which would allow for either importing and modifying a Prado gate to mount the spare or using an innovative (and arguably more robust) option with the ACC Garage Becky tire mount. Properly installing this mount is a genuine project, but the instructions are adequate, and it really is a step-by-step affair. It took me a few days to fully complete, as I spent all the time required to address any issues discovered along the way. This included additional painting and rust protection, along with a measure-three-times, cut-once pace. The kit comes with a sturdy, thoughtfully designed tire mount that bolts through the Lexus gate and is reinforced with plates, angle shims, and a lower striker ramp. This ramp secures to the rear body crossover and helps to support the weight of the tire and wheel combination. Additional attention is needed in mounting the license plate, improved backup light, and relocating the backup camera. In the end, it was one of the most satisfying and transformative modifications, changing the appearance of the GX. The spare tire is now immediately accessible (not buried in the mud), and the factory tire well can be used for either an extra spare, or for my purposes, additional water and fuel storage. It should be noted that the rear-mounted spare does reduce visibility slightly, and shifts the center of gravity up marginally as well.
With the spare relocated, I turned my attention toward removing the factory running boards, which is a few-minute job, yielding a big improvement in ground clearance. It has the extra benefit of reducing weight by 30 pounds from the vehicle, offsetting the added 19 pounds from the new tire mount. At this point, I considered rock sliders but ultimately held off due to the payload impact. Rock sliders that can additionally serve as side steps have real advantages in the field, but I felt comfortable going without because of the ground clearance gained (details later in this article), relying on the watchful eye of a spotter when warranted. Others may choose differently based on their use case.
Captions (clockwise): With solo travel a regular prospect,I always fit a high-quality 12-volt recovery winch. The Warn Zeon 10-S fit perfectly in the bull bar and was complemented by Warn’s Sidewinder hook replacement. | The rear suspension took somework to incorporate a lift using the factory airbags, including configuring a custom spacer and adjusting the height sensors. The rear BP-51s are long travel, so spacing the bagsis critical to prevent damageat full extension. | It is easy to discount IFS for backcountry travel, but the Toyota suspension configuration deliversin the field. The GX now ridesand handles better than stockwhile benefiting from moreground clearance. | One of the modifications thatmost impressed me was theTimbren bump stops. Their taller profile and progressive designare just what the GX ordered. | The tire mount requires measuring with care and then drillingfour times into the back door. Additional work is needed to accommodate a relocated license bracket and lighting. The endresult is worth the effort. | The AEV Crestone wheelslook great on the GX and are complemented by the talland narrow Toyo A/T IIIs.
SUSPENSION AND TIRES
Through the years, I have grown fond of working on what cannot be seen first. And few modifications serve the driver as much every day (while being mostly unseen) than a good suspension. With each passing year, suspension systems get stronger, more adjustable, and ultimately more usable for travel. The GX already starts with a good suspension from the factory, with driver-adjustable compression damping, and a long-travel, multi-height rear airbag configuration. We wanted to retain those attributes, improving on them with a fully integrated system. There were several goals to achieve, including additional ground clearance, while also increasing the spring rate on the front springs to accommodate the weight of a bull bar and winch. The factory front rate is too soft for even an unloaded vehicle, so I needed an additional 200+ pound rate increase (with an adjustable preload) to improve the overall handling and accommodate the weight of the ARB bumper.
After some deliberation, I selected the Old Man Emu BP-51 front coilover and rear remote reservoir shocks, an ideal confluence of service life, performance, durability, and adjustability. A principal performance advantage is the internal bypass configuration, which permits significant changes to fluid flow throughout the shock stroke. In practical terms, it allows for a supple ride in the middle of the shock range and improved vehicle control during large suspension events. Another feature I wanted was rebound and compression adjustability. I intended to run the vehicle without a front anti-sway bar [Editor’s Note: This is not a recommended or endorsed practice.], which makes precise rebound control more essential to manage sway or load transitions. The shocks also happen to be a work of art and are designed for long-distance remote travel in harsh conditions. They installed easily, but the rear did require some adjustment to accommodate the stone guard and the mismatch between airbag length and shock stroke.
For the suspension, another objective was to retain the airbags in the rear, which provides a significant improvement in ride quality while load leveling for variable payloads. As my daily driver, the Lexus can be near empty, or fully loaded with camping gear, or pulling a heavy trailer, so the flexibility of airbags is worth retaining. This required spacing the airbags up from the axle mounts by 60 millimeters using an Air Lift 52420 spacer, customized to the lower pin on the factory airbags. The ride adjustment rods were then adjusted to level the vehicle. This modification is critical, as the airbags are too short for the BP-51 shock stroke (something learned during local testing, not in the shop).
As the last step, I installed the new Timbren Active Off-Road bump stops front and rear. These taller, progressive-rate, natural rubber jounces have provided several critical benefits for the project. Most importantly, the rear jounces are taller than the factory ones, protecting the rear sheet metal from tire contact on full compression. They serve as a secondary spring should an airbag fail, allowing me to drive off the trail. It was an airbag failure that initially inspired me to install these units, as the vehicle went down to factory bumps and the tires made fender contact—time to call a tow truck. The front Timbren jounces are only slightly taller than factory but work in concert with the BP-51s to provide an impressive amount of control. The suspension now works exactly as desired on the highway, at high speed on the dirt, and during low-speed maximum articulation events.
Tires and wheels are one of the most essential modifications to any overland vehicle, so I paid particular attention to the tire size selected. I have been a longtime fan of a tall and narrow tire, which improves fitment and reduces weight. One of my favorite sizes is a 255/80 R17, which measures over 33 inches tall and only 10 inches wide. Toyo’s new A/T IIIs were on the list to test, and they have exceeded my expectations for highway, dirt trails, and even snow and ice. The tires were mounted to (in my opinion) the best wheel available today for overland travel, the American Expedition Vehicles Crestone Dualsport wheel, which is a true DOT-approved beadlock. This allows for extremely low pressures in snow and sand without fear of losing a bead and also improves remote field service of a tire for patching and other repairs.
As a safeguard, we installed one of my favorite accessories, the ARB bull bar, which provides full protection from animal strikes or light trail damage, inspiring respect from all but semi-truck drivers in developing countries. The ARB Summit bar is designed for the Prado 120, but it does work on the GX 470 with some patience, creating a template for the bumper wings to trim the Lexus fender flares. It not only works ideally for this application but again transforms the appearance of the vehicle. The bumper also serves as a platform to mount a Warn Zeon 10-S, one of the most effective models for this size vehicle and remote applications. It retains a wired remote and benefits from a sealed Albright solenoid, synthetic line, and improved overall line speed. Lastly, a set of ARB LED lights was installed to provide ample nighttime illumination at all speeds.
To address underbody protection, I again turned to ARB, and their full complement of pressed and folded, 3-millimeter, laser-cut skid plates. The zinc-coated skid plates mount to factory attachment points and significantly improve resistance to trail damage, particularly in rocky terrain. While they do add some weight to the GX, the vehicle stayed within GVWR; the weight of the plates is extremely low in the chassis, actually improving the center of gravity.
The last consideration to the exterior was to take advantage of the open factory spare tire location to mount a set of Trail’d water tanks. At 6 gallons each, two of them mount right where the original spare was and even utilize the factory lifting winch to lift and secure the tanks. They provide more than enough water for a long weekend of camping. If my travels extend beyond the reach of the EPA (i.e., outside of the USA), then these tanks also work perfectly for emergency fuel storage. The key with auxiliary fuel storage is only to use them when needed and transfer the fuel as soon as possible. Twelve gallons of fuel weighs over 80 pounds but can be invaluable during those rare occasions when maximum range is needed.
Overall, the Lexus GX has proven to be an exceptionally reliable and genuinely pleasant vehicle to drive. It has served equally as a daily driver and as a long-distance backcountry tourer. Underneath all that leather and wood trim, this vehicle has the heart of a Land Cruiser, and that reason alone makes it a solid choice for overlanding.
Editors note: Lexus GX platforms are not approved applications for ARB products. Installing vehicle-specific ARB products on applications other than those approved by ARB will void the warranty.
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