Eaton 915A388 Detroit Truetrac (Fits Dana 60 Axles With 35 Splines and a 4.56 or Higher Gear Ratio) | 1979-2016 Ford F250/F350 Super Duty 4WD

Features:

• Fits Dana 60 axles with 35 splines
• Compatible with 4.56 and higher gear ratios
• Supports 1.5 inch axle shaft diameter
• Helical gear design for smooth torque transfer
• No clutches or wearable parts to maintain
• Automatically biases torque to the wheel with grip
• Operates quietly with no driver input required
• Works in front or rear axle applications
• Ideal for trucks with larger wheels and tires
• Built for 9.75 inch ring gear setups
• Heavy duty construction for lasting durability
• Fits 1979–2016 Ford F250 and F350 4WD models

Get Confident Traction Without Giving Up Comfort

If your Super Duty is geared aggressively and running bigger tires, you need a differential that can keep up without sacrificing your truck’s road manners. The Eaton 915A388 Detroit Truetrac gives you the best of both worlds, quiet, automatic torque transfer when you need extra traction, and smooth, open-diff behavior when you don’t. Whether you're climbing loose hills, driving through snow, or navigating uneven terrain, the Truetrac keeps both wheels working together without the harshness of a full locker. It’s completely automatic, so there’s no switch to press or electronics to fail, just a smart, mechanical solution that does its job without you ever thinking about it. Perfect for trucks with 4.56 or higher gears, this differential handles high torque loads while keeping things calm on the pavement. If you're after a serious traction upgrade that still drives great on the street, this is one of the most dependable options you can bolt in. And with Eaton's proven durability, it's built to handle whatever you throw at it.

Helical Gear Limited Slip For Aggressive Gear Builds

The Eaton 915A388 Truetrac is a torque-sensing limited slip differential designed for Dana 60 axles with 35 spline shafts and 4.56 or higher gear ratios. It features a parallel-axis planetary helical gear design that automatically biases torque to the wheel with the most traction, providing quiet and seamless operation in both front and rear axle applications. Unlike traditional clutch-based limited slips, the Truetrac contains no wearable parts, meaning no maintenance and consistent long-term performance. It supports 1.5 inch axle shaft diameters and 9.75 inch ring gear setups, making it ideal for Super Duty owners running aggressive gear ratios and oversized tires. The automatic engagement makes it especially useful for mixed-use trucks that see both street and trail time. It performs like an open differential under normal conditions but immediately engages when traction is lost, restoring forward motion without any input from the driver. For trucks originally equipped with OE lockers, custom modifications may be required during installation. This Truetrac offers a refined solution for those wanting a strong, mechanical limited slip that works quietly and effectively in real-world conditions.

Fits: 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016 Ford F250/F350 Super Duty 4WD

Notes:

• Only fits Dana 60 axles with 35 splines
• Compatible with 4.56 or higher gear ratios
• Requires 1.5 inch axle shaft diameter
• Designed for 9.75 inch ring gear applications
• Works in both front and rear axle positions
• Uses helical gear design for automatic torque biasing
• No clutches or wearable parts inside the unit
• Operates quietly with smooth engagement under load
• Fully mechanical with no need for switches or wiring
• Ideal for trucks with large tires and high torque builds
• OE locker-equipped vehicles may require modifications
• Fits 1979–2016 Ford F250 and F350 Super Duty 4WD