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Product Summary

Ford 9 Inch, Limited Slip Differential Type

  • Hand-assembled by our trained technicians for an unbeatable combination of quality and value
  • Precision assembly for the correct backlash, preload, and proper amount of pinion shims to ensure the correct pattern on the ring gear teeth
  • Ideal for street tires and medium horsepower applications
  • Lightweight aluminum housing has forged caps and extra beef where it's needed while saving 20 lbs. over cast iron versions
  • Clutch style positraction differential gives limited slip performance and quiet operation (no gears clicking!)

Key Specs

MFG. Part #
BrandSpeedway Motors
Differential TypeLimited Slip

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Assembled by Professionals

Hand-assembled by trained experts in-house, our Ford 9-inch third members are built from quality components with an exact step-by-step process. We bring this combination of precision assembly and quality components to you at a price that can’t be beat. We trust these third members so much, they’re the go-to choice for our own rides, from the street to the track. 

Lightweight Aluminum Center Section

This brand new carrier housing is built to take street/strip abuse without the fear of breaking. Our aluminum housing has forged caps and extra beef where it's needed. The aluminum case will save you 20 lbs. over the cast iron version. 

Thick, forged steel bearing caps surround the carrier bearings, all securely held in place with precision Grade 8 cap screws. The improvements continue with rugged billet steel adjuster nuts and heavy-duty keepers to ensure your ring gear settings are maintained. All mounting surfaces are precision machined to ensure a consistent, flat surface for a positive gasket seal (no more leaks on your shop floor). An oil fill plug is included.

Precision Assembled for Proper Ring Gear Teeth Pattern

Getting a proper pattern on the ring gear teeth is crucial. Our time-proven, step-by-step process ensures the correct backlash, preload, and proper amount of pinion shims to ensure the correct pattern on the ring gear teeth. Our gears use cold-rolled 8620 steel, known for its long-wear and durability.

To ensure a proper gear pattern, we use a stronger forged aluminum “Daytona” style pinion bearing support to maintain that critical pinion depth setting. Stronger due to its larger bearings, our Daytona pinion support also uses the spacer-and-shim setup to maintain critical pinion depth settings under high load, unlike traditional crush sleeves which often compress further, take out your preload and lead to failure. With solid bearing spacers and the proper shims, we eliminate this problem and make setting preload easy and repeatable during installation, service, and gear changes. Since preload is already set, simply torque the pinion nut to 160 ft./lbs. and you’re good to go. The pinion gear is connected to our new, forged steel “Ford short”, 1310-type pinion yoke. 

Clutch-Style Posi Differential with Proven Performance 

Our clutch-style posi differential gives you maximum traction. Based on the original limited-slip designs of the OEMs, these differential units provide the added benefits of experience over millions of miles and decades of proven reliability. A clutch-style operation means no clicking around corners and our posis feature heat-treated spider gears in a forged steel case. We’ve taken this posi to the next step in performance with increased clutch pressure and holding power, suiting it well for heavy-duty street car applications.   

  • Clutch style, spider gear differential = proven reliability 
  • Spring-loaded clutch pack with improved grip over OEM designs 
  • Ideal for street tires and medium horsepower applications 
  • Housed in a Fully Machined, Reinforced Forged Steel Case

Proven Reliability

We run what we sell. Our third member units are the go-to choice for our own rides and we have built these units to last with high-quality hardware and components. Tapered steel roller bearings minimize friction, better handle thrust loads, and increase load-carrying capacity. The ring gears are assembled with Grade 9 bolts with a tensile strength of 180,000 psi, a 15% increase over Grade 8 hardware.  Heavy-duty Grade 8 carrier cap bolts, a lock-style pinion nut with pre-applied Loctite and high-quality grade 5 pinion support bolts make our third member near-bulletproof. 

Units include a Viton® pinion seal providing long-lasting oil and chemical resistance. This seal retains elasticity up to 399°F (204°C) and intermittently up to 600°F (316°C) This high temp seal helps eliminate pinion leaks, reduces maintenance, and keeps the third member properly lubricated. A carrier-to-housing gasket is available separately. 

Our hand-assembled Ford 9 inch third-member assemblies are made-to-order. We keep a supply of the most popular gears in stock, with most units built within 2-3 days. Our third-member units are shipped in a durable, reusable poly storage case, perfect for keeping multiple gear sets stored and ready for the track.

Features

  • Hand-assembled by our trained technicians for an unbeatable combination of quality and value
  • Track-tested durability in our own cars – we race what we sell
  • Precision assembly for the correct backlash, preload, and proper amount of pinion shims to ensure the correct pattern on the ring gear teeth 
  • Ring and pinion gears of 8620 cold-rolled steel for long wear
  • Lightweight aluminum housing has forged caps and extra beef where it's needed while saving 20 lbs. over cast iron versions
  • Large bearing forged aluminum “Daytona” style pinion bearing supports for strength and reliability
  • Spacer and shim setup maintains critical pinion depth settings and easier to service than traditional crush sleeves
  • Clutch style positraction differential gives limited-slip performance and quiet operation (no gears clicking!)
  • Ring gears assembled with Grade 9 hardware, 15% stronger in tensile strength than Grade 8
  • Viton® pinion seal, resistant to chemicals and high temperatures
  • Grade 8 Carrier cap bolts
  • Lock-style pinion nut with pre-applied Loctite®
  • Grade 5 pinion support bolts
  • Includes form-fitted, reusable red poly storage case

Charts

Warranties

No warranty is offered or made for durability or specific performance. No warranty is offered for commercial, off road, street performance, or racing use.

Specifications

KEY SPECS
MFG. Part #
BrandSpeedway Motors
Differential TypeLimited Slip
GENERAL
Housing MaterialAluminum
Gear Ratio
Axle Splines
Yoke U-Joint Series1310
Yoke Width3-7/32"
U-Joint Cap Size1-1/16"
Spool WeightStandard
Ring Gear WeightStandard
Sold in QuantityEach
Gear MaterialSteel