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Detroit Locker 913A315 Truetrac Limited-Slip Differential 30-Spline GM 12-Bolt Truck

Manufacturer

Detroit Locker

<p>Detroit Locker, now part of the Eaton family, represents one of the most storied names in performance drivetrain components. The legendary Eaton Detroit Locker began the revolution in performance differentials and continues to set the standard for automatic locking differential technology. Originally developed for off-highway and heavy-duty applications, the Detroit Locker became a factory option in muscle cars during the 1960s and has since earned a reputation among professional racers, rock crawlers, and off-road enthusiasts who demand maximum traction in the most challenging conditions.</p><h3>How Detroit Locker Technology Works</h3><p>The Detroit Locker is a 100% automatic locking differential that provides ultimate traction for mild to extreme vehicle applications. Unlike limited-slip differentials or open differentials, the Detroit Locker operates in a fully locked state during straight-line driving, capturing 100% of available torque and distributing it equally to both wheels. In turns and maneuvers, the internal components unlock to allow one wheel to spin faster or slower as necessary (free wheel). When the vehicle returns to a straight-line driving path, the components re-engage and provide power to both wheel ends. This wheel-speed-sensitive design ensures that power is always delivered where it's needed most, whether you're navigating mud, snow, rocks, or the drag strip.</p><h3>Built for Extreme Performance</h3><p>The Detroit Locker's reputation for durability stems from its robust engineering and high-quality manufacturing. Detroit Lockers have a very high "strength density", thanks to continual process innovation, advanced metallurgy, and ultramodern machining methods. The design is engineered to handle more torque than the axle shafts themselves can transmit, making it an ideal choice for high-horsepower builds, competitive racing, and severe-duty towing applications. From drag racing to rock crawling, the Detroit Locker delivers consistent, reliable performance under conditions that would overwhelm conventional differentials.</p><h3>Premium <a href="/178-detroit-locker-differential-carrier-13098">Differential Carriers</a> and Components</h3><p>Detroit Locker's <a href="/178-detroit-locker-differential-carrier-13098">differential carrier</a> assemblies are precision-engineered to integrate seamlessly with a wide range of axle configurations. These carrier units house the sophisticated locking mechanism that defines Detroit Locker performance, providing the foundation for extreme traction applications. The brand also offers components for <a href="/178-detroit-locker-differential-2304">differentials</a> across numerous vehicle platforms and <a href="/178-detroit-locker-automatic-transmission-valve-body-12200">automatic transmission valve bodies</a> for select applications, ensuring comprehensive drivetrain solutions for performance enthusiasts.</p><h3>Applications and Uses</h3><p>Detroit Locker differentials are engineered for a diverse range of demanding applications. Below is a list of common uses: Street/Strip, Drag racing, Circle track / NASCAR, Rock crawling, Off-road, Utility Vehicles, Light, medium and heavy trucks. While many enthusiasts use Detroit Lockers for everyday street driving, the aggressive engagement characteristics make them particularly well-suited for racing and off-road environments where maximum traction is paramount. The brand's extensive application coverage spans Ford, Chevrolet, Dodge, Jeep, and many other popular platforms, with options for both front and rear axle installations.</p>

Part Number

913A315
07/17/2036 8:37 PM
Sale Price

$723.54

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Usually delivered within 2 days

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Product Details

The Detroit Locker 913A315 Truetrac is a helical gear-style limited-slip differential designed for GM 8.875-inch (12-bolt) truck rear ends with 30-spline axles and 3.73 and higher gear ratios. This maintenance-free differential uses a patented design of parallel-axis planetary helix gears to provide smooth, automatic torque distribution between wheels for enhanced traction and control.

Key Features:

  • Helical gear design eliminates wearable clutch packs - no maintenance required
  • Automatic torque transfer to the wheel with better traction
  • Smooth, quiet operation in both forward and reverse
  • Works like an open differential under normal conditions, engages instantly when traction is needed
  • Fits GM 12-bolt truck applications 1982 and older
  • Compatible with both C-clip and non-C-clip axle configurations
  • 30-spline axle shafts with 1.30-inch diameter
  • Steel construction for maximum durability

Technical Specifications:

  • Ring gear size: 8.875 inches (GM 12-bolt truck)
  • Axle spline count: 30-spline
  • Gear ratio compatibility: 3.73 and up (numerically higher)
  • Cover bolts: 12-bolt configuration
  • Requires petroleum/mineral-based GL-5 80W-90 gear oil (synthetic oils and friction modifiers should not be used)

The Detroit Truetrac differential is ideal for a wide range of applications including trucks, SUVs, motor homes, emergency vehicles, and performance applications where dependable traction is essential. Special bearings are required for GM 8.5-inch and 8.6-inch axle installations - consult fitment guide for bearing specifications based on your vehicle year.

Products specifications

Aftermarket Carrier Style

Detroit Truetrac

Axle Shaft Spline Quantity

30

Carrier Material

Steel

Carrier Series

4

Cover Bolts

12

Manufacturer of Axle

GM

Notes

Fits 3.73 gear ratio and nurmerically higher.

Quantity

Sold individually.

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