Choosing the Right Rear Axle for an Expedition Truck: Our Dana 80 Swap Explained
Goodbye Stock Axle, Hello Dana 80: Building a Better Foundation for Rufus
The rear axle is the backbone of any truck’s drivetrain. It’s the workhorse that takes engine power and delivers it to the ground, keeping you moving forward. In most builds—especially for heavy-duty overland or expedition trucks—the rear axle choice can make or break performance.
When we began building Rufus, our expedition truck, we quickly realized the factory axle could work… but only with significant modifications. Instead, we decided a rear axle swap was the smarter move for reliability, gearing options, and long-term parts availability. Here’s how we made the decision and why we ultimately chose a Dana 80.
Why Consider Replacing the Factory Axle?
What We Liked About the Stock Axle
Brand New – Built in a factory, ready to go, and already ours—no sourcing or rebuilding required.
Perfect Fit – Designed for the truck, so the shocks, springs, brake lines, and ABS all lined up without modification.
Ease of Swap– The stock axle would have been the simplest option for installation.
Why It Didn’t Make the Cut
6-Lug Wheels (6x222.25) – Too narrow for our desired tires, and aftermarket wheel options are rare in the U.S.. Matching the front axle would require costly changes.
Limited Gear & Locker Choices – The factory axle came with 4.30:1 gearing and an open differential—too tall for our needs and lacking a locker or limited slip.
Parts Availability – These cab-over truck axles are uncommon in North America, making parts sourcing more difficult.
Related post: Why We Chose Our Transfer Case for the 4x4 Conversion
What We Needed in a Replacement Axle
Before hunting for a swap candidate, we listed our must-haves:
Weight Rating – Strong enough to handle our heavy build without limiting payload.
Gear & Locker Options – Flexible ratios and a selectable or automatic locker.
Global Parts Availability – Easy to source parts anywhere, especially in the U.S.
Heavy-Duty Brakes – Capable of stopping a loaded expedition truck.
ABS Compatibility – Ideally with factory ABS or space to install sensors.
Common Bolt Pattern – Widely available wheel fitment, preferably 8x6.5.
Correct Width – No narrowing or widening required.
Axle Options We Considered
We narrowed our search to heavy-duty U.S. pickup truck axles—widely available, proven in demanding conditions, and offering the specs we needed.
Dana 80 – Used by all Big Three manufacturers (1988–2005). GAWR up to 13,500 lbs, 11.25" ring gear, disc or drum brakes, ABS-ready.
AAM 11.5 – Found in Dodge and GM pickups from 2001 onward. GAWR 10,000 lbs, 11.5" ring gear, disc brakes, ABS.
GM 14-Bolt – Produced since 1973 and used by GM. GAWR 8,600 lbs, 10.5" ring gear, disc or drum brakes, ABS options.
Why We Chose the Dana 80
We selected the Dana 80 - Key reasons:
Width - the Dana 80 was factory made in a width to fit Rufus without modification, after a bit of digging we found an axle in the width we needed.
11,000 GAWR – Easily handles our build’s weight, the axle we sourced came with an 11,000 GAWR
8x6.5 Bolt Pattern – Wide wheel choice and easy parts sourcing and global availability.
Heavy-Duty Drum Brakes – extra wide 3.5” shoes for reliable heavy duty stopping power.
Our dana 80 Modifications
To meet our exact needs, we:
Performed a full rebuild.
Swapped gearing.
Installed a limited slip differential for improved traction.
Machined hubs for ABS tone rings and welded brackets for sensors.
Replaced spring and shock mounts with aftermarket weld-on brackets to adjust pinion angle and shock position.
Installed new inner and outer Timken bearings and Stage 8 locking nuts.
The Result
This Dana 80 rear axle swap gives Rufus the strength, gearing, braking, and parts availability we wanted for long-term overland travel. With the right axle under the truck, we know our expedition rig can carry the load—on-road or far off it—for years to come.
