G-Wagen Service
May 22, 2025
Ever wondered what it takes to turn a stock Mercedes G55 AMG into a global expedition truck? At Alliance Auto Care in Loveland, Colorado, we did exactly that—transforming a 2006 G55 into a portal-axle-equipped overland rig capable of going anywhere, anytime.
Here’s how we built it, what it took, and what makes it one of the most capable G-Wagons we’ve ever put on the road.
How to make a G-Wagen that started life as a low-slung, fast-moving AMG truck, to a powerhouse off-road beast? You need these upgrades:
Upgrades include:
Portal axles (Extreme Ratio) with CTIS integration
King 2.5” remote reservoir shocks and JWO 2” lift springs
38×13.50R18 Toyo Mud Terrains on beadlock wheels
AFN bumpers, brush guards, and 10,000 lb synthetic rope winch
MBRP cat-back exhaust
Full lighting system with Baja Designs LP6s
Onboard air via dual ARB twin compressors
Central Tire Inflation System (CTIS) with in-cabin controls
Front Runner rack, drawer system, and fridge mount
Fox adjustable steering stabilizer
Upgraded Brembo brakes
Apple CarPlay Alpine command center
This truck can air up tires on the fly, carry an overland tent, and still cruise at 65 mph with comfort and stability.
The portal axles are the heart of this build. By lifting the axle without modifying suspension geometry, we preserved factory ride quality and dramatically improved ground clearance.
Why go portal?
Allows for massive 38” tires without crazy suspension mods
Provides gear reduction at the hub, preserving factory drivability
Keeps suspension geometry intact
Enables true off-road capability with factory steering behavior
Compared to traditional lifts, portal axles are heavier and more complex—but they solve major off-road challenges and are fully serviceable.
On the road, the G55 portal build performs better than you’d expect.
Minimal shimmy once tires warm up
Stable cruising at 65+ mph
Great visibility thanks to the added height
Surprisingly composed with 160 lb wheels
Thanks to upgraded brakes, King shocks, and a tight alignment, it’s not just drivable—it’s enjoyable.
Transform your truck with field service in mind:
5-speed automatic transmission is global, reliable, and easy to source
113 supercharged V8 is proven, powerful, and widely supported
Dual ARB compressors are mounted outside the cabin and globally serviceable
All plumbing and brackets were custom-fabricated to avoid failure points
Add in TIG-welded reinforcement braces and used red Loctite to ensure nothing backs out under extreme use.
Everything under this truck has been optimized:
King shocks dampen heavy wheels and unsprung mass
OEM radius arm bushings hold up better than poly in extreme conditions
Braided brake lines and diff lock lines for durability
Custom mounts for onboard air and stabilizers keep everything tight and rattle-free
We also designed custom cooling and trans line solutions to integrate with the new bumper setup—making the front end clean, aggressive, and fully functional.
The rig in our featured video includes a complete auxiliary lighting system powered via in-cabin switches. Scene lights, LP6s, and rear lights all feed into a clean setup with full functionality.
Other accessories include:
Wind-deflector-compatible rack
Custom fridge drawer
Rear ladder and rooftop tent compatibility
Integrated spare tire carrier (to protect the rear door from 160 lb of rubber)
Curb weight: ~7,000 lbs
Tire size: 38×13.50R18
Lift: 2” + portal axle lift (~5–6” net gain)
Brake system: Brembo upgraded with 18” wheels to accommodate size
Suspension travel & control: King 2.5” shocks with remote reservoirs
Fuel economy: Don’t ask. (Single digits—but worth every drop)
Great question. Here’s why this G55 build makes sense:
It retains the legendary 113 supercharged motor
The 5-speed auto is simple and globally supported
It avoids turbo complexity
It’s easier to service on the trail or overseas
It’s a true custom setup—tailored for performance and reliability
At Alliance Auto Care we build flexible, functional expedition vehicle. With onboard air, CTIS, portal gearing, and trail-grade clearance, it’s ready for Moab, Baja, the Rockies—or the Arctic.
Everything was engineered in-house by the Alliance Auto Care team. It’s serviceable, durable, and designed for the long haul.
If this G-Wagon portal build speaks to you, let’s talk. Whether you’re planning your first G or your tenth, we’ll help you spec and build something truly one of a kind.
Contact Joe Gocher at Alliance Auto Care in Loveland, Colorado.
Get in touch with Joe Gocher and the team at Alliance Auto Care—we’ll get your truck squared away the right way.
Welcome to Alliance Auto Care, where quality auto care meets convenience. We specialize in servicing European and high-end vehicles, including Porsche, Audi, Land Rover, BMW, Lexus, G Wagons and Mercedes.
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