Strange S-Trac Differential Fits 9" Ford With 35 Spline Axles Requires Aftermarket 3.250" Bore Case


Part Number: N1980

Application – Ford 9″ with 35 spline axles

Aftermarket 3.250″ bore case
Axles with 30 degree pressure angle

Strange 35 Spline S-Trac
This helical gear differential offers smooth and progressive power transfer
Superior design and quality make it ideal for the most abusive Street/Track applications

Torque Biased, Mechanical & Clutchless
• Maximizes traction and acceleration
• Dependable and maintenance free
• Quiet operation

Forged Steel Case Halves
• Heat treated
• Fully machined
• Provides a light, durable, and rigid unit

Internal Gear Pocket Geometry
• Minimizes stress risers
• Increases service life

Dry Film Solid Lubricant Coating
• Applied to thrust surfaces
• Minimizes component wear

9310 Steel Pinion Gears
• Chrome moly material
• Provides the ultimate in torque carrying capacity

Aggressive Gear Helix Angle
• Promotes superior torque bias
• Excels in situations of unequal traction

All Internal Gears Made from 9310 Steel
• Vacuum heat treated for superior strength
• Additionally cold treated to optimize fatigue life and reduce wear

Proven Quality
• Designed, machined, & assembled by Strange
• Materials made in the USA

Gear Lube
Will adversely affect unit operation and void warranty

Use Only Petroleum Based 85W-140 Gear Oil

Related Components
S-Series 3.250″ bore case…………. N2206
Pro Iron 3.250″ bore case…………. N1906
Pro HD Alum 3.250″ case kit……… P3203

Side bearings & races……………….. D1590

Alloy axle package………………. P3502 / P3504


Strange Helical Differential For Ford 9in

The Strange 35 Spline S-Trac Differential is a helical differential that offers smooth and progressive power transfer. Its superior design and quality make it ideal for the most abusive Street/Track applications. The torque biasing S Trac Differential is purely mechanical which eliminates the need for clutches. It provides quiet operation while maximizing tire traction and vehicle acceleration.

The Strange Helical Differential

Built with forged steel case halves that are heat treated and fully machined to minimize weight and provide a rigid mounting surface for the ring gear resulting in improved gear life. Internal gear pocket geometry is designed to minimize stress risers increasing component life. The housing encapsulates precision manufactured gears, including 9310 steel pinion gears, that provide exceptional strength. All internal gears, pinion and side gears, are vacuum heat treated to increase strength and also cold treated to extend service life while reducing wear. A dry film solid lubricant coating is applied to friction surfaces to minimize wear.

Ideal for road racing, off-road and autocross applications.

The S Trac Helical Differential is recommended for full bodied street/track cars that run the 1/4 mile in the low 9 seconds or slower. For Drag Race Only vehicles, Strange Engineering recommends using a spool. The seamless operation also makes it ideal for road racing, off-road and autocross. This premium differential unit carries a limited lifetime replacement warranty to the original purchaser.

Parts List and Installation Guide pdf File

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