Eaton 917A738 Detroit TrueTrac LSD for Ford 8.8" IFS Front 31-Spline All Ratios

Vehicle Fitment

• 2009-2023 Ford F-150 4WD (8.8 in. IFS Front Axle, 31-Spline Snap-Ring Style, All Gear Ratios)

Fitment Notes

• Fits the Ford 8.8 in. independent front suspension (IFS) front axle only - this is the front differential in 4WD F-150 models; it is NOT the Ford 8.8 in. rear axle found in F-150 and Mustang applications
• Snap-ring axle style - confirm your F-150 front axle uses snap-ring (C-clip style) axle retention before ordering
• Compatible with all available factory gear ratios in this axle - no ratio-specific selection required
• 31-spline axle shaft interface with a 1.32 in. axle shaft diameter
• Some retailers list fitment extending to 2024-2025 F-150 - verify directly against your specific vehicle's front axle configuration before purchasing if you have a 2024 or later model
• Lubrication: Eaton requires a quality petroleum/mineral-based GL-5 80W90 gear oil - do NOT use synthetic gear oil or friction modifier additives
• Sold as an individual differential unit - installation kit (bearings, shims, seals, pinion seal, crush sleeve, cover gasket) sold separately; consult an appropriate Ford 8.8 in. IFS-specific installation kit for this application
• Installation instructions available for download via Eaton's product page

Features

• Detroit TrueTrac - Eaton's helical-gear limited-slip differential, using a patented parallel-axis planetary helix gear design to automatically and smoothly transfer torque to the front wheel with better traction without friction discs, clutches, or driver input
• Clutchless design - no friction clutch packs or wearable internal components; torque bias is generated entirely through helical gear geometry, making the unit completely maintenance-free for its service life
• Fully automatic torque biasing - senses front wheel speed differentiation and automatically redirects torque from the slipping wheel to the gripping wheel with no switches, electronics, or driver action required at any point
• Compatible with all factory gear ratios - no ratio-specific setup required; this unit covers every available gear ratio for the F-150 8.8 in. IFS front axle
• Smooth, progressive engagement - transitions between open-differential behavior and torque transfer gradually, without the wheel hop, understeer, or steering column feedback associated with full locking front differentials during on-road cornering and parking maneuvers
• Functions identically in forward and reverse - gear-driven torque biasing operates in both drive directions, providing traction improvement regardless of direction
• Quiet, durable operation - the all-gear internal design produces no ratcheting, clicking, or mechanical noise during normal driving; behaves like an open differential in everyday 4WD use on paved roads
• Product weight: 25 lbs; Ring gear size: 8.8 in.; Axle shaft diameter: 1.32 in.; 31-spline interface
• Suitable for street and muscle, light trail, rock crawl, work truck and towing, drag racing, circle track, and restoration applications per Eaton's vehicle usage classifications

Specifications

• Part Number: 917A738
• Product Type: Detroit TrueTrac Helical-Gear Limited-Slip Differential
• Axle Application: Ford 8.8 in. IFS - Front (Snap-Ring Axle Style)
• Axle Shaft Spline Count: 31
• Axle Shaft Diameter: 1.32 in.
• Ring Gear Size: 8.8 in.
• Ring Gear Ratio Requirement: All Ratios
• Differential Type: Helical-Gear Limited Slip (Clutchless, Automatic Torque Biasing)
• Operation: Fully Automatic (no driver input required)
• Lubrication: Petroleum/Mineral-Based GL-5 80W90 Gear Oil Only - No Synthetic, No Friction Modifier
• Product Weight: 25 lbs
• Quantity: Sold Individually (installation kit not included)

Included Components

• 1x Eaton Detroit TrueTrac Differential Unit (917A738)
• Note: Bearings, shims, pinion seal, crush sleeve, ring gear bolts, and differential cover gasket are NOT included - order an appropriate Ford 8.8 in. IFS front axle installation kit separately

Product Description

The Eaton 917A738 is a Detroit TrueTrac helical-gear limited-slip differential for the Ford 8.8 in. independent front suspension (IFS) front axle on 2009-2023 Ford F-150 4WD models. It is important to note that this is the front differential for 4WD F-150 trucks - it is not the Ford 8.8 in. rear axle unit found in the F-150 and Mustang. The unit uses a snap-ring (C-clip) axle style, 31-spline shafts with a 1.32 in. shaft diameter, and is compatible with all factory gear ratios available in this axle without any ratio-specific selection required.

The TrueTrac uses Eaton's patented parallel-axis planetary helix gear arrangement to produce torque bias through gear geometry rather than friction. When one front wheel loses traction, the helical gear set automatically develops an axial load proportional to the torque differential, redirecting drive torque to the wheel with better grip. This occurs smoothly and progressively with zero driver input - no switch, no solenoid, no electronics. There are no clutch packs to wear, no additive requirements, and no service intervals; the TrueTrac is maintenance-free for the life of the unit. On dry pavement, the unit operates silently and identically to an open differential, making it well-suited to daily-driven 4WD F-150 trucks where front locker harshness during turns and parking maneuvers would be unacceptable. It works equally in forward and reverse.

Eaton requires petroleum/mineral-based GL-5 80W90 gear oil; synthetic oil and friction modifier additives must not be used. The 917A738 is sold as a differential unit only - an appropriate installation kit for the Ford 8.8 in. IFS front axle must be ordered separately. Some retailers indicate this unit may also fit 2024-2025 F-150 models - if you have a 2024 or newer F-150, verify your vehicle's front axle configuration against this unit's specifications before purchasing. Application guide and installation instructions are available for download through Eaton's website.