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The Eaton Detroit Truetrac Differential (Part #913A561) is a premium limited-slip differential designed for Ford 8.8-inch axles with 31-spline shafts. Built for superior traction and durability, the Detroit Truetrac is Eaton’s helical-gear style LSD—offering smooth, automatic torque biasing without clutches or friction plates. Ideal for both on-road performance and off-road strength, it delivers consistent, maintenance-free operation across a wide range of driving conditions. Whether it’s for drag racing, towing, or rock crawling, this differential ensures maximum traction and control where you need it most.
Helical-gear limited-slip design for smooth, automatic torque transfer
Maintenance-free—no clutches or friction materials to wear out
Durable forged steel construction for long-lasting performance
Proven design trusted in both high-performance and heavy-duty applications
Engineered for Ford 8.8-inch, 31-spline axle setups
Works with all gear ratios
| Attribute | Details |
|---|---|
| Brand | Eaton |
| Product Type | Detroit Truetrac Differential |
| Part Number | 913A561 |
| Differential Type | Limited Slip (LSD) |
| Axle Type | Ford 8.8 in |
| Spline Count | 31 |
| Axle Shaft Diameter | 1.32 in |
| Ring Gear Ratio | All |
| Ring Gear Size | 8.8 in |
| Product Weight | 25.25 lb |
| Model Years | Vehicle Make | Vehicle Type / Model | Axle Location | Axle Description | Gear Ratio |
|---|---|---|---|---|---|
| 1986–2014 | Ford, Lincoln, Mercury | Passenger Car | Rear | Ford C-Clip | All |
| 1983–2014 | Ford | Small Truck, Minivan, SUV | Rear | Ford C-Clip | All |
| 1987–2014 | Ford | Half-Ton Truck, Van, SUV | Rear | Ford C-Clip | All |
On Road: Drag Racing, Restoration, Circle Track, Work Truck/Towing, Street & Muscle
Off-Road: Light Trail/Sand Sports, Rock Crawl, Extreme Off-Road, Work Truck/Towing
