The Detroit Truetrac Is Now Available For The 2015-2022 Ford F-150

If you’ve been wanting to up your 2015-2022 Ford F-150’s off-road game, there’s good news from Eaton. The Detroit Truetrac limited-slip differential is now available in front and rear fitments for said trucks equipped with 8.8-inch axles.

Eaton Detroit Truetrac Is A Helical Gear-Type Limited Slip

The Truetrac differential is the leading, and original, helical gear-type limited-slip differential in the industry. It features a patented design of parallel axis, planetary helical gears, which ensures a seamless and noiseless automatic distribution of torque. The Truetrac engages and disengages without any driver action required. This smooth power transfer is imperceptible to the driver, even in front-wheel-drive axles. Notably, the Truetrac’s smooth operation does not impact braking characteristics or fuel consumption. It also has no wearable parts and requires no maintenance.

In typical driving scenarios, the Truetrac Differential functions akin to an open differential. However, when encountering challenging conditions like wet, muddy, icy, or loose terrain, its design automatically redirects power to the wheel with the highest traction. This instantaneous response to torque feedback results in necessary traction at any speed.

The Eaton Detroit Truetrac excels in both front and rear axles, so it offers versatile performance. Its proven design, coupled with cost-effectiveness, positions it as not only a great choice for the F-150, but also a wide array of vehicle applications.

The Eaton Detroit Truetrac (part number 917A738) for the 8.8-inch axle in the front of the Ford F-150 works with all gear ratios.

How The Eaton Detroit Truetrac Limited-Slip Differential Works

But how does the Truetrac limited-slip differential work, exactly? Well, the Truetrac functions like an open differential in normal conditions. When necessary, it transfers torque to the wheel with optimal traction. This transfer can reach up to 3.5 times more torque to the high-traction wheel, achieved through helical side gears and pinions. The bias ratio, determined by the pressure exerted by these components against the differential case, facilitates this transfer. Furthermore, the bias performance of the Truetrac complements and enhances brake-based traction control systems. Truetrac designs have been engineered to operate within a continuous torque range of 2,500 lb-ft. To enhance capacity, larger gears and additional pinion sets can be utilized.

On challenging terrains, the Truetrac automatically redirects power to the wheel with the best traction, counteracting imbalanced gear forces. The Truetrac promptly responds to torque feedback, ensuring necessary traction under any circumstances and at any speed.

Although Truetracs offer the highest bias ratio in the forward direction, they also exhibit a slightly reduced bias ratio in the reverse direction or during engine braking.

Available For Many Applications

In addition to the 8.8-inch axle-equipped 2015-2022 Ford F-150 applications, the Truetrac is available for Chrysler, Dana, Ford, and GM axles. It’s also used in Hummer, Kia, Land Rover, Nissan, and Toyota vehicles.  Truetrac differentials are engineered to work efficiently in front and rear axles and transfer cases. Designs exist for C-clip, full-float, semi-float, and snap-ring style axle configurations.

It’s worth noting that at the time of this writing there are also several other new Truetrac applications available. They include the 2021-2022 Bronco without the factory locking diff, 2011-up Ram V6 and V8 trucks, and 2015-up GM 1/2-ton trucks.

The Truetrac (part number 917A739) for the 8.8-inch rear axle works with 3.31-up gear ratios.

Truetrac Fast Facts

  • Improved traction relative to other rear wheel and four wheel drive vehicles
  • Maintenance free – requires no special lubrication or friction modifiers
  • Lifetime torque bias retention
  • Simple, proven design
  • Smooth and quiet operation
  • Limits wheel spin-out and improves handling
  • Performs open, until needed

Tech Notes

For optimal Truetrac performance, the company recommends using a quality petroleum-based GL5-rated gear oil with a viscosity grade of 80W-90. Synthetic oils are not recommended. Additionally, friction modifiers should not be used as they can negatively impact overall performance by reducing the differential bias.

The Eaton Detroit Truetrac (part number 917A738) for the 8.8-inch axle in the front of the Ford F-150 works with all gear ratios. The Truetrac (part number 917A739) for the 8.8-inch rear axle works with 3.31-up gear ratios.

About Eaton

Eaton can trace its roots back to 1911 when a young entrepreneur named Joseph Eaton decided to invest in a new idea in transportation — the first gear-driven truck axle. Today, in addition to the Truetrac, Eaton offers off-roaders traction-enhancing choices including the Detroit Locker and ELocker differentials.

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About the author

Ken Brubaker

After learning to drive in a 1967 Rambler American, Ken was addicted to all things with an engine and wheels. He has owned a wide range of vehicles including a pair of 1977 Pontiac Trans Ams and a 1997 Jeep Wrangler.
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