Made in USA
S-Series with 31-Spline Trac Lock 3.70 Ratio
InfoVehicle Info Needed
STRANGE ENGINEERINGPART NUMBER: 873-PJ9ST31S370

S-Series with 31-Spline Trac Lock 3.70 Ratio

$1,48387
ShippingShips on 11/06/2026
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S-Series with 31-Spline Trac Lock
    S-Series with 31-Spline Trac Lock
  • 3.70 Ratio

    Strange Engineering Complete 3rd Members are available in S-Series with 31-spline and 35-spline, Pro Iron Case and Pro Aluminum case with 35-spline designs.

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    S-Series with 31-Spline Trac Lock
    The 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, quiet street operation, and longevity.

    S-Series with 35-Spline Spool
    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, increased strength in critical areas, and longevity. The Strange S-Series Spool provides a light yet rigid mounting surface for decreased ring gear deflection. Due to the standard (street) gear set, these packages are for drag racing applications up to 750 HP (Strange recommends a Pro Gear for 750+ HP). Spools are for drag racing only.

    Pro Iron Case with 35-Spline Spool
    The Strange Pro Iron case is cast from premium nodular iron and manufactured by Strange Engineering in the USA. The Pro Iron nodular iron case with chrome-moly caps features additional material in all critical areas, allowing for the case to withstand the most abusive applications. The Strange S-Series Spool provides a lightweight and rigid mounting surface for decreased ring gear deflection. This case should be used for applications exceeding 750 HP. The Pro Gear used in these setups is made from high-impact 9310 steel. Spools and Pro Gear Sets are for drag racing only.

    Pro Aluminum Case with 35-Spline Spool
    The Strange lightweight aluminum case is designed for applications where weight reduction is crucial and gear life is not of the utmost importance. This lightweight case is made from a high-tensile aluminum alloy, plus features forged aluminum caps to help minimize cap distortion. The Strange 35-spline lightweight pro steel spool provides rigid mounting to reduce ring gear deflection while weighing only 8.2 pounds. The Pro Gear used in these setups is made from high-impact 9310 steel. Spools and Pro Gear Sets are for drag racing only.

    Note: Strange Center Sections are ready to install and include 2-piece transport case

Part TypeThird Member Assembly
Product LineStrange Engineering Complete 3rd Member (Ready-to-Install Assembly)
BrandSTRANGE ENGINEERING
Package Height14.8
Package Width15.0
Package Length18.0
Weight85.15 PG
Part CategoryPerformance Parts
Part FitmentSemi Universal
Vendor Part NumberPJ9ST31S370
Package Qty1
Package TypeEA
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