Speedmaster Third Member Assembly Nodular 31-Spline TorqueWorm LSD Ford 9”
Highlights
- 6-Pinion Gear Differential
- Reduces Internal Load Stress
- Heat-Treated For Durability
- Pre-Loaded And Faster-Reacting
Speedmaster Ford 9” Nodular Third Member Assembly with 31-Spline TorqueWorm LSD.
The Speedmaster Ford 9” Nodular Third Member Assembly with 31-Spline TorqueWorm LSD is an unparalleled choice for serious automotive enthusiasts. This top-of-the-line assembly features a high-quality nodular iron through-bolt design center section with billet bearing caps that have extra material added for ultimate strength and durability. The unique TorqueWorm 6-pinion gear type limited-slip differential is preloaded and faster-reacting, spreading the stress over a greater surface area to reduce internal load.
Features and Benefits:
- Great for daily drivers, street rods, and race cars
- High-quality nodular iron thru-bolt design center section
- Billet bearing caps have extra material added
- Unique TorqueWorm 6-pinion gear type limited-slip differential
- Preloaded and faster-reacting unit
- Spreads stress over a greater surface area to reduce internal load
- EN36 material is made for racing applications
- 8620 chrome-nickel-Moly steel outer case for long life and strength
- CNC machined high-quality gear sets
- Heat-treated for extreme durability and high impact
- Lapped for correct tooth contact and smoothness
- TDS long-style billet yokes CNC machined to exact specifications
- Available in several gear ratios
Made of EN36 material that's specifically designed for racing applications, the 8620 chrome-nickel-Moly steel outer case provides long-lasting strength, while the CNC machined high-quality gear sets are heat-treated for extreme durability and high impact. This assembly is lapped for correct tooth contact and smoothness and comes with TDS long-style billet yokes that are CNC machined to exact specifications. With several gear ratios available, this assembly is a great choice for daily drivers, street rods, and race cars.
Specifications:
- Part type: third member complete assembly
- Case style: Ford 9”
- Case material: nodular steel
- Main cap material: aluminum
- Main cap retention style: thru-bolt
- Carrier bearing diameter (in): 3.006”
- Pinion support bolt quantity: 5
- Standard pinion location: yes
- Ring gear load bolt: no
- Ring and pinion included: yes
- Ring and pinion ratio 3.50, 3.70, 3.89, or 4.11
- Yoke included: yes
- Yoke style: 1350 series
- Bearings included: yes
- Carrier type: 31-Spline Speedmaster Torque Worm LSD
Vehicle Fitment:
- 1965-1973 Mustangs
- 1948-1979 F-100s
- 1966-1977 Broncos
Please Note: These 3rd members are to be used with a mineral-based oil of a range of EP140 Extreme pressure at a minimum. NO split grades such as 85/140 (these are not recommended). Failure to use the correct oil can result in gear damage and noise.
California Residents: Proposition 65 Warning
Related Categories: Mustang Parts, Mustang Rear Axle, Mustang Differentials, Ford Bronco Parts, Ford F-100 Parts
Installation Difficulty

Intermediate skill is required for this installation.
Installation Instructions
Vehicle Fitment
This product will fit the following Bronco years:
This product will fit the following F-100 years:
- 1948,
- 1949,
- 1950,
- 1951,
- 1952,
- 1953,
- 1954,
- 1955,
- 1956,
- 1957,
- 1958,
- 1959,
- 1960,
- 1961,
- 1962,
- 1963,
- 1964,
- 1965,
- 1966,
- 1967,
- 1968,
- 1969,
- 1970,
- 1971,
- 1972,
- 1973,
- 1974,
- 1975,
- 1976,
- 1977,
- 1978,
- 1979,
This product will fit the following Mustang years: