S-Series with 31-Spline Trac Lock 3.89 Ratio

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STRANGE ENGINEERINGPART NUMBER: 873-PJ9ST31S389

S-Series with 31-Spline Trac Lock 3.89 Ratio

Name: S-Series with 31-Spline Trac Lock 3.89 Ratio
Brand: STRANGE ENGINEERING
SKU: 873-PJ9ST31S389
Price: 1853.28 USD
Availability: InStock

^$1,853²⁸

Ships on 09/10/2026

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^$582²⁹

555-60684

Ford 9 Inch Posi Traction Third Member Assembly [3:89 Ratio 31-Spline]

^$1,270⁹⁹

S-Series with 31-Spline Trac Lock

S-Series with 31-Spline Trac Lock

3.89 Ratio

The Strange S-Series is cast from premium nodular iron and manufactured by Strange Engineering in the USA. The S-case is machined to exact tolerances and has a radial rib design for superior rigidity, allowing for quiet street operation and longevity. Center sections are ready to install and ship with a 2-piece transport case.

Features:

Strange Nodular Iron S-Series Case
Innovative Radial Rib Design
Premium Reinforced Nodular Iron Caps
Iron Daytona Style Pinion Support (same support used by the majority of NASCAR teams)
Large 1350 Series Pinion Yoke
31-Spline Trac Lock Differential
Timken Bearings and National Seals
Ideal for Street Applications

Note: Gasket NOT included

Part TypeThird Member Assembly

BrandSTRANGE ENGINEERING

Package Height13.9

Package Width15.0

Package Length18.25

Weight86.0 PG

Part CategoryPerformance Parts

Ring And Pinion Ratio3.89

QuantitySold individually

Part FitmentSemi Universal

Vendor Part NumberPJ9ST31S389

Package Qty1

Package TypeEA

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