The Ultimate Towing Traction: Lock Your 1-Ton Axle for Serious Duty.
When you are piloting a Ford F-350 Super Duty or a heavy-duty Ram, you are relying on massive torque to move massive weight. Unfortunately, the factory limited-slip differentials in these Dana 70 and Dana 80 rear ends often wear out or fail to provide true two-wheel drive when you are stuck in mud with a loaded gooseneck. The ARB RD174 is the solution: a competition-grade locking differential built to handle the extreme abuse of 1-ton trucks.
At Overland Truck Store, we recommend this locker for the heaviest builds—whether you are hauling a slide-in camper, towing heavy machinery, or building a dedicated recovery rig. Unlike automatic lockers that can cause dangerous handling quirks while towing on the highway, the ARB Air Locker remains completely open for smooth, predictable street driving. But when you hit the switch, it instantly locks your massive 37-spline shafts together, ensuring every foot-pound of torque reaches the ground.
This unit features a heavy-duty two-piece case and forged internal gears designed specifically to cope with the shock loads of high-torque diesel engines and 40+ inch tires.
Features & Specs:
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Application:
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Ford: F-350 Super Duty (1999-2016)
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Other: Ford E-350 / E-450 Vans (Check specific years/axles)
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Axle Fitment: Fits Dana 70 and Dana 80 rear axles.
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Spline Count: Requires 37 Spline axle shafts.
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Carrier Break: Typically fits ratios 4.10 and numerically higher (e.g., 4.56, 4.88, 5.13).
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Performance: Provides 100% traction on demand without sacrificing towing stability or tire wear.
Installer Note: This is a massive locker for 37-spline axles only. Many standard Dana 70s came with 32 or 35 splines, and some Dana 80s vary. You must confirm your spline count and gear ratio carrier break before ordering. Installation requires a dedicated air compressor (sold separately).
