Inside the ford bronco big bend Drivetrain: Dana AdvanTEK Axle Specs
Ford’s Legacy of Power and Innovation: Inside the Bronco Big Bend Drivetrain – Dana AdvanTEK Axle Specs
You’re cruising down the highway in your Big Bend, and somewhere deep in the back of your mind, you wonder: what’s actually spinning those wheels when you twist the knob into 4H? Is the hardware under there legit, or is Ford just slapping stickers on a mall crawler?
Here’s the truth that separates casual owners from true enthusiasts: the 2021–2026 Ford Bronco Big Bend rolls off the line with genuine Dana axles—the same company that’s been supplying axles for off-road vehicles since the 1940s . But not all Dana axles are created equal, and the Big Bend’s setup is specifically engineered for its place in the Bronco hierarchy. Understanding what’s underneath your truck helps you know its limits—and its potential.
TL;DR;
The Ford Bronco Big Bend trim comes standard with a Dana 35™ AdvanTEK® front-drive unit (M190) and a Dana 44™ AdvanTEK® rear axle (M220) . The front axle uses a 3.73, 4.27, or 4.46 gear ratio depending on configuration, with an open differential (laser-welded ring gear) . The rear axle is the more robust Dana 44 M220, available with either an open differential or an electronic locker depending on options . This combination gives the Big Bend legitimate off-road capability while keeping costs manageable. Compare this to the Badlands, which gets the beefier Dana 44 M210 front axle and standard lockers front and rear .
Key Takeaways
- Front Axle: Dana 35 AdvanTEK M190 independent front-drive unit – smaller than the Badlands’ M210 but perfectly adequate for 33-inch tires and moderate trails
- Rear Axle: Dana 44 AdvanTEK M220 solid axle – shared with higher trims, this is the stronger component in the Big Bend’s setup
- Gear Ratios Available: 3.73, 4.27, or 4.46 depending on engine, transmission, and optional packages
- Differential Type: Standard open differentials; electronic locker available in the rear with optional packages
- Upgrade Path: The Ultimate Dana 44 AdvanTEK front-drive unit from Dana Aftermarket bolts directly in place when you’re ready for lockers and deeper gearing
The Dana Legacy: Why It Matters
Ever wonder why off-road enthusiasts get excited about axle brand names while casual drivers couldn’t care less?
Dana has been building axles for off-road vehicles since the 1940s. They supplied the Dana 25 and 27 for the original Willys MB, the Dana 30 and 44 for first-generation Broncos, and the Dana 44 TTB for third- and fourth-gen Broncos . When you see that Dana name cast into the housing, you’re looking at over 80 years of off-road engineering experience .
For the sixth-generation Bronco, Dana partnered with Ford to develop a family of AdvanTEK® axles specifically designed for this platform . These aren’t off-the-shelf parts—they’re engineered for the Bronco’s weight, power, and intended use.
“Dana AdvanTEK axles are rugged, yet lightweight, and offer best-in-class noise, vibration, and harshness (NVH) performance with greater power density” .
The Big Bend’s Axle Lineup: By the Numbers
Let’s break down exactly what’s living under your Big Bend.
Front Axle: Dana 35™ AdvanTEK® M190 FDU
The front axle on the Big Bend is the Dana 35 AdvanTEK M190 Front-Drive Unit (FDU) . This is an independent front suspension (IFS) setup—meaning each front wheel can move independently, which improves ride quality on pavement and trail compliance.
M190 Specifications:
| Specification | Detail |
|---|---|
| Axle Model | Dana 35 AdvanTEK M190 FDU |
| Ring Gear Size | Smaller than M210 (exact diameter not published, but designed for 3.73–4.46 ratios) |
| Available Ratios | 3.73, 4.27, 4.46 |
| Differential Type | Open (laser-welded ring gear) |
| Spline Count | Not specified for OE, but aftermarket upgrades offer 32-spline options |
The M190 is the “entry-level” AdvanTEK front axle, but don’t let that fool you—it’s still a legit piece of off-road hardware. It’s designed to handle the 2.3L EcoBoost’s 300 hp and 325 lb-ft of torque, and it’s perfectly capable with 32- or 33-inch tires on moderate trails.
One technical source notes: “New Broncos roll off the line with these axles, which are built to handle the Bronco’s high-torque engine” .
Rear Axle: Dana 44™ AdvanTEK® M220
Here’s where the Big Bend gets a pleasant surprise: the rear axle is the same Dana 44 AdvanTEK M220 used on higher trims . This is a solid rear axle (SRA) design—a traditional live axle that provides excellent articulation and durability.
M220 Specifications:
| Specification | Detail |
|---|---|
| Axle Model | Dana 44 AdvanTEK M220 |
| Ring Gear Size | 220 mm (new generation) or 226 mm (traditional)—sources vary |
| Torque Capacity | 8,200 Nm (approximately 6,048 lb-ft at the ring gear) |
| Available Ratios | 3.73, 4.27, 4.46 |
| Differential Type | Open (standard) or Electronic Locker (optional) |
| Construction | Salisbury-style solid axle |
The M220 is a significant piece of hardware. Its 8,200 Nm torque capacity means it can handle serious power and big tires. The 220 mm ring gear (in the AdvanTEK version) actually achieves the same torque capacity as the older 226 mm design through improved gear geometry and materials .
Fun fact: The AdvanTEK gearing achieves the same torque capacity with a smaller ring gear through enhanced power density and optimized gear geometry .
Gear Ratios: What Your Big Bend Came With
The gear ratio in your Big Bend depends on several factors: engine choice, transmission, and whether you optioned the locking rear differential.
Standard Gearing by Configuration
| Configuration | Front Axle Ratio | Rear Axle Ratio | Notes |
|---|---|---|---|
| Base 2.3L / Auto | 3.73 | 3.73 | Open diffs standard |
| Base 2.3L / Manual | 4.46 | 4.46 | Manual transmission requires 4.46 gearing |
| With 4×4 Advanced Package | 4.27 | 4.27 | Optional package, may include rear locker |
| With Locking Rear Diff | 3.73 or 4.27 | 3.73 or 4.27 (ELD) | Ratio depends on engine/trans |
The manual transmission’s 4.46 gearing is worth noting—it’s significantly steeper than the automatic’s 3.73, which helps with off-road crawling but means higher RPMs on the highway .
What Those Numbers Mean
- 3.73 gears: Better highway fuel economy, lower RPMs at cruising speed
- 4.27 gears: Compromise between highway and off-road performance
- 4.46 gears: Better off-road torque multiplication, higher highway RPMs
The Spicer parts catalog confirms these ratios are achieved through laser-welded ring gears on the open differential models .
Open vs. Locking Differentials: What’s the Difference?
The Big Bend’s standard open differentials work fine for most driving, but understanding their limitations helps you know when to engage 4WD and when to consider upgrades.
Open Differential (Standard)
An open differential sends power to the wheel with the least resistance. On pavement, that’s fine—both wheels have traction. Off-road, if one wheel lifts or spins on loose surface, all the power goes to that wheel, and the one with grip gets nothing.
Pros: Smooth operation, low maintenance, good fuel economy
Cons: Limited off-road traction in low-grip situations
Electronic Locker (Optional)
When engaged, an electronic locker forces both wheels on an axle to spin together. If one tire is in the air, the other still gets power. This is a game-changer for serious off-roading.
Pros: Maximum traction when engaged, open behavior when disengaged
Cons: Higher cost, slightly more complexity
The Big Bend can be ordered with the optional rear locker, which uses an Eaton ELocker design through Dana . If you plan to off-road, this is worth seeking out.
How the Big Bend Compares to Other Trims
To understand where the Big Bend fits, let’s look at the axle lineup across the Bronco range:
| Trim Level | Front Axle | Rear Axle | Standard Lockers | Notes |
|---|---|---|---|---|
| Base / Big Bend / Outer Banks | Dana 35 M190 | Dana 44 M220 | No (rear optional) | M190 front, open diffs standard |
| Black Diamond | Dana 35 M190 | Dana 44 M220 | No (rear optional) | Similar to Big Bend |
| Badlands / Wildtrak / First Edition | Dana 44 M210 | Dana 44 M220 | Front and rear | M210 front is stronger |
| Raptor | Dana 44 AdvanTEK (210 mm ring gear) | Dana 50 AdvanTEK (235 mm ring gear) | Front and rear | Heavy-duty everything |
| Sasquatch Package (any trim) | Upgraded to match trim | Upgraded to match trim | Front and rear | 4.70 gearing standard |
The key difference is the front axle. The Badlands and above get the Dana 44 M210 front axle, which has a larger ring gear and is designed for more aggressive off-roading and larger tires . The Big Bend’s M190 is lighter and more efficient, but it has lower ultimate strength.
One technical source explains: “Lesser variants make do with AdvanTEK M190 independent front suspension and a Dana 44 AdvanTEK M220 solid rear axle while off-road variants level up to the M210” .
The Sasquatch Package: What It Changes
If your Big Bend came with the Sasquatch Package, your axle setup changes significantly:
- Front axle: Remains M190, but gets 4.70 gearing and an electronic locker
- Rear axle: Remains M220, but gets 4.70 gearing and an electronic locker
- Tires: 35-inch (up from 32- or 33-inch)
The 4.70 gearing is much steeper than standard, which helps turn those heavy 35-inch tires. However, the M190 front axle with 4.70 gears is working harder than it would with smaller tires—something to keep in mind if you plan extreme rock crawling.
The Spicer parts catalog confirms: “Sasquatch Package (any model): Front Axle Dana 44 AdvanTEK FDU (M210 FDU) 4.70 ELD” —wait, that says M210? This suggests Sasquatch may actually upgrade the front axle on some trims. Let’s clarify.
Correction: According to the Spicer parts data, the Sasquatch Package uses a Dana 44 M210 front axle with 4.70 gearing and electronic locker . This means if your Big Bend has Sasquatch, you actually get the stronger front axle—a significant upgrade.
Aftermarket Upgrades: The Ultimate Dana 44
For Big Bend owners who want more capability—lockers, deeper gearing, or just stronger components—Dana offers the Ultimate Dana 44 AdvanTEK Front-Drive Unit as a direct bolt-in upgrade .
Ultimate Dana 44 Specs:
| Feature | Detail |
|---|---|
| Axle Model | Ultimate Dana 44 AdvanTEK FDU |
| Available Ratios | 3.73, 4.10, 4.46, 4.56, 4.70, 4.88, 5.13, 5.38 |
| Spline Count | 29 or 32 spline options |
| Differential | Electronic locker standard |
| Construction | Cast-iron center housing, FAD-eliminated solid tube |
| Price | Approximately $3,799 |
This axle replaces the M190 entirely, giving you the strength of the M210 (or better) with your choice of gearing. It’s designed for “extreme off-roading” and can handle tire sizes up to 37 inches or more .
Dana notes: “The Ultimate Dana 44 AdvanTEK front-drive unit provides increased strength and durability in every facet and offers a choice of gear ratios to help you achieve optimum performance in your rig after upgrading tire size” .
For the rear, the stock M220 is already quite strong, but Dana offers the Ultimate Dana 60 Semi-Float for those who need even more capacity .
Visualizing the Bronco Axle Lineup
This chart shows the axle configurations across different 2021–2026 Bronco trims:
Ford Bronco: Axle Specifications by Trim
Front and rear axle configurations across Bronco trims.
What This Means for Your Big Bend
Daily Driving
For pavement pounding and light trail use, the Big Bend’s axle setup is more than adequate. The M190 front axle is smooth and efficient, and the M220 rear is overkill for daily duties—which means it’ll last forever.
Moderate Off-Roading
If you’re hitting forest service roads, sandy washes, and moderate trails, your Big Bend will handle it fine—especially with the optional rear locker. The M190 front is the limiting factor; keep tire sizes at 33 inches or smaller, and avoid situations where you’re bouncing the front end hard.
Serious Upgrades
If you’re dreaming of 35s, lockers front and rear, and rock crawling, you have two choices:
- Trade up to a Badlands (comes with M210 front and lockers)
- Upgrade your Big Bend with the Ultimate Dana 44 front axle
The Ultimate Dana 44 bolts directly in place of your M190 and transforms the truck’s capability .
“Fully loaded and ready to install right out of the crate, Ultimate Dana 44 AdvanTEK front-drive units are built to handle the Bronco SUV’s high-torque engine, provide increased strength and durability” .
FAQ Section
1. What axles come standard on the Ford Bronco Big Bend?
The Big Bend comes with a Dana 35 AdvanTEK M190 front-drive unit (independent front suspension) and a Dana 44 AdvanTEK M220 rear axle (solid axle). The front is open differential standard; the rear may be open or electronic locker depending on options .
2. What gear ratios are available on the Big Bend?
Available ratios include 3.73, 4.27, and 4.46. The manual transmission requires 4.46 gearing. The optional locking rear diff can be paired with 3.73 or 4.27 depending on configuration .
3. Can I add a locking differential to my Big Bend?
If your Big Bend didn’t come with the factory locker, you can add an aftermarket locker. Dana offers the Ultimate Dana 44 front axle with integrated electronic locker, and Eaton ELocker options exist for the rear .
4. How does the Big Bend’s front axle differ from the Badlands?
The Big Bend uses the smaller Dana 35 M190 front axle, while the Badlands gets the larger Dana 44 M210. The M210 has a larger ring gear and is designed for more aggressive off-roading and larger tires .
5. What’s the Sasquatch Package axle setup on a Big Bend?
If you option Sasquatch on a Big Bend, you get upgraded to the Dana 44 M210 front axle with 4.70 gearing and electronic locker, plus the M220 rear with 4.70 gearing and electronic locker, and 35-inch tires .
6. Can I put 35-inch tires on a stock Big Bend?
Technically yes, but the stock M190 front axle with 3.73 or 4.27 gearing will struggle with 35s. You’ll notice reduced acceleration, higher strain on components, and potential durability issues. Regearing to at least 4.70 is recommended .
7. What’s the torque capacity of the Dana 44 M220 rear axle?
The AdvanTEK M220 has a torque capacity of 8,200 Nm (approximately 6,048 lb-ft) at the ring gear—far more than the engine can produce, meaning the axle itself is not the weak link .
8. Is the Dana 35 M190 front axle weak?
“Weak” is relative. The M190 is designed for its intended use—it’s lighter and more efficient than the M210. For 33-inch tires and moderate trails, it’s perfectly adequate. It becomes a limitation only with 35s and hardcore rock crawling .
9. What aftermarket axles fit the Big Bend?
Dana offers the Ultimate Dana 44 AdvanTEK front-drive unit as a direct bolt-in replacement for the M190. It comes with your choice of gear ratios (3.73–5.38) and an electronic locker standard .
10. Does the Big Bend have the same rear axle as the Raptor?
No. The Raptor uses a Dana 50 AdvanTEK rear axle with 235 mm ring gear, while the Big Bend uses the Dana 44 M220 with 220/226 mm ring gear. The Raptor’s axle is significantly heavier-duty .
11. What’s the spline count on Big Bend axle shafts?
Stock specifications aren’t published, but aftermarket upgrades like the Ultimate Dana 44 offer 29 or 32 spline options. The higher spline count provides greater strength .
12. Can I regear my Big Bend without swapping axles?
Yes. Spicer offers ring and pinion gear sets for both the M190 front and M220 rear in various ratios. However, regearing requires professional installation and should be done as a matched set front and rear .
References
- Spicer Parts: Ring and Pinion Gearing for Ford Bronco
- Spicer Parts: Front-Drive Unit Axles for Ford Bronco from Dana
- DanaProParts: Ultimate Dana 44 AdvanTEK Front-Drive Unit
- Off Road Xtreme: Ultimate Dana 60 Semi-Float Axle for Jeep and Bronco
- autoevolution: 2021 Ford Bronco Official Technical Specifications
- 汽车之家: Ford Bronco Raptor Axle Specifications (Chinese)
- MOTOR: Dana Introduces Ultimate Dana 60 and Ultimate Dana 44 for Bronco
Call to Action
Got a Big Bend and wondering what axle setup you have? Pop your head under the truck and look for the Dana tags—or check your window sticker for the axle code. Drop your build details in the comments below and share what trails you’re tackling!
