Product Summary

Rear Position, 31 Axle Splines, Semi-Floating Axle Type

  • Designed to replace the original 1964-1966 Mustang rearend housing
  • Compatible with the stock rear suspension found in your Mustang
  • Hand-assembled by our trained technicians for an unbeatable combination of quality and value
  • Ideal for street tires and medium horsepower applications
  • Brake kits include two bolt-on caliper brackets, two 11 1/4" vented rotors, two GM metric emergency brake style calipers, brake pads and hardware

Comes as a Kit

Key Specs

Axle Splines31
Axle TypeSemi-Floating
Brakes IncludedYes
Material TypeSteel

Need To Know

Made to Order

This custom item will ship when completed

Quick and Easy Returns

Return Policy

Speedway Motors 9100226 Details

Rear Housing and Axles

These bolt-in rear axle packages are designed to replace the original '64-'66 Mustang rearend housing and are compatible with the stock rear suspension found in your Mustang. The major advantages gained by upgrading to a Ford 9" axle include greatly increased strength (reliability) and tremendous aftermarket support (parts availability). Here are the features you'll find in our fabricated Ford 9 Inch axle kits:

  • New stamped steel housing center piece
  • New billet steel housing ends with oil seal surface ("Big New Ford" Torino-style)
  • 3" O.D. DOM 3/16" wall axle tubes
  • 31-spline axles w/ bearings, studs & retainers
  • 1/2"-20 wheel studs, 2" long
  • 5 x 4-1/2" wheel bolt pattern
  • Jig welded suspension brackets for stock style suspension
  • Built to stock width


Housing Studs

Housing studs and ring gear bolts complete the package for your racing or street use 9" Ford axle.

Side bell thru bolts torque to 40-45 lbs.

Knurl diameter .398-.403 "


Third Member

As featured on Classic Truck’s Week to Wicked. Watch the transformation here!

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. 

Tough, Nodular Iron Center Section

Our Ford 9 Inch Nodular Iron Third Member Center Section Carrier starts with a NEW casting with over 4 lbs. of additional material in critical areas. Nodular (ductile) iron is much more resistant to fracturing than OEM “gray” iron. Extra ribbing reinforces the case and rearmost pinion support (pilot bearing). 

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 use cold-rolled 8620 steel, known for its long-wear and durability.

To ensure a proper gear pattern, we use a stronger “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.

This differential has performed well in our Week to Wicked 1952 Chevy Truck, handling the job of transferring a 430 HP GM Performance LS3 to the ground.   

  • 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.


  • 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
  • Nodular iron housing is stronger than OEM “gray” iron and has 4 lbs of additional reinforcement
  • Large bearing “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


Install Kit

Make the installation of your new Posi-Traction Third Member a breeze! We've packed together some of the most commonly needed items to ease your installation with one click!

Kit Includes:

  • 919-0916 Speedway 3rd Member Mounting Hardware for 8/9 Inch Rearends
    • Used to attach the 3rd member (pumpkin) to the rearend housing
    • Works with Ford 8" and 9" rear axles
    • Includes aluminum washers
  • 919-2300 Speedway 9 Inch Ford Rearend Axle Housing 3rd Member Pumpkin Gasket
    • Reusable Differential Gasket
    • Steel Core
    • Non-Stick Coating
  • 910-48319 Universal Drive Shaft U-Bolts, 1-1/16 Inch Cap
  • 795-9751 Valvoline VV975 Synpower 75W90 Gear Oil, 3 Quarts
    • Thermally stable, extreme-pressure gear lubricant
    • Designed to operate in both high and low extreme-temperature conditions
    • Recommended for limited-slip hypoid differentials and is compatible with conventional gear lubricants
    • Maintains excellent low-temperature fluid protection
    • Provides outstanding thermal stability for cleanliness and longer service life
    • Contains special additives to assist in protecting gear teeth from rust and corrosion
    • Contains special additives to reduce chattering in limited-slip differentials
    • 3 quarts
  • 60780301 Red Line 80301 Limited-Slip Friction Modifier Additive, 4 oz.
    • Compatible with both petroleum and synthetic gear oils
    • Reduces break-in temps as much as 50°F
    • Add 1oz at a time to clutch-type limited slip or posi-traction units to eliminate chatter
    • Exceeds API GL-5 specifications
    • Engineered to provide the highest degree of protection and efficiency for better mileage, longer drain intervals, and less wear
    • 4 ounce bottle
    • Recommended Dosage:
      • Use 4% for prevention of limited slip chatter in broken-in units (typical one 4 oz. bottle) or 4 to 8% for the break-in of new differentials.
      • In non-limited-slip racing differentials and quick-change units using the Red Line ShockProof Gear Oils an additional 3 to 6% Red Line Limited-Slip Differential Friction-Modifier / Break-In Additive is recommended.

795-9751 Material Safety Data Sheet

80301 Safety Data Sheet (PDF)

80301 Product Data Sheet (PDF)


Brake Kit

Disc Brake Stopping Power at a Great Value

This economical disc brake kit for Ford 9 inch and 8 Inch axles is simple to install and provides big stopping power, at a price nearly the same as replacing original drum brakes. That Ford rear end handles the power to make it go, but these binders clamp down when you say whoa! Today’s average family sedan can stop from 60 MPH in 120 feet, at nearly 1G of deceleration. You need the same stopping power. Your passengers, you and your car deserve the confidence of disc brakes and our kit delivers that confidence with exceptional value.

Superior to Drum Brakes

Aftermarket disc brakes are superior to original drums in many ways: more braking force, less brake fade, and easier service. Stopping power starts with our newly manufactured GM Metric D154 style single piston calipers, commonly found on 1978-88 GM G-Body and A-Body cars. Large 11-1/4” diameter, 1” thick vented rotors provide more stopping leverage than common 9” or 10” drum brakes. Brake pads are easier to change than drum shoes, and our brake kit includes a street-friendly organic compound for long rotor/pad life. Replacement pads are common sized, available from your local auto parts store. Looking for more aggressive stopping power? We carry race-grade D154 disc brake pads that drop in just as easily.

Fits Ford 9 Inch and 8 Inch Housings

This disc brake kit fits Ford 8” axles, as well as passenger car Ford 9 inch axle housings with “big bearing” ends (3.150” O.D. bearing, found on passenger cars from 1974-79). Included bracketry will adapt this kit to both “new style” and “old style” Ford 9 inch housing flanges with the 3/8” bearing retainer bolt holes. Bracket spacers are also included, allowing this kit to work with axle flange offsets of 2-3/8” or 2-1/2” common on Ford 9 inch passenger car rear ends. Axle flange offset is measured from the axle housing flange face (with bearing retainer removed) to the axle shaft flange face (side where the brake rotor/drum rides, including the thickness of the axle flange). 


Kit Includes

(1) Speedway Ford 9 Inch Bolt-In Rear End Axle for 1964-66 Mustang

(1) 9 Inch Ford Rearend Axle Housing 3rd Member Carrier Studs

(1) Ford 9 Inch Posi Differential 3rd Member, 31 Spl, 3.50 Gear Ratio

(1) Speedway Ford 9 Inch Posi Traction Third Member Install Kit

(1) Ford 9 Inch Bolt-On Rear Disc Brake Kit w/ E-Brake Caliper


Speedway Motors 9100226 Specifications

MFG. Part #9100226
BrandSpeedway Motors
Axle Splines31
Axle TypeSemi-Floating
Brakes IncludedYes
Material TypeSteel
Gear Ratio3.50:1
Differential TypeLimited Slip
Housing MaterialSteel
Bolt Pattern5 on 4.5"
Yoke U-Joint Series1310
Hardware IncludedYes
Rotors IncludedYes
Differential IncludedYes
Sold in QuantityKit