The Ford 9-inch differential, often shortened to "9-inch third member," is legendary among car enthusiasts, particularly those involved in hot rodding, racing, and off-roading. Its robust design, readily available parts, and immense strength have solidified its place as a go-to rear end for high-performance builds for decades. This comprehensive guide will explore the 9-inch Ford third member in detail, addressing common questions and providing valuable information for those considering using one in their project.
What is a Ford 9-Inch Third Member?
The "third member" refers to the differential assembly itself—the heart of the rear axle. In the context of the Ford 9-inch, it's a remarkably strong and versatile unit that allows the two rear wheels to rotate at different speeds, essential for navigating turns. Its "9-inch" designation comes from the diameter of the ring gear, a key component within the differential. This large ring gear, combined with robust construction, makes the 9-inch capable of handling significant power and torque.
What Makes the Ford 9-Inch Third Member So Popular?
The 9-inch's enduring popularity stems from several key features:
- Strength and Durability: The heavy-duty design can withstand extreme stress, making it ideal for high-powered vehicles and demanding applications.
- Parts Availability: Decades of production and aftermarket support mean parts are readily available and relatively inexpensive compared to other high-performance differentials.
- Customization Options: Numerous aftermarket companies offer a wide range of upgrades and modifications, allowing for precise tuning to specific needs and performance goals. This includes gear ratios, posi-traction units, and various housing options.
- Versatility: The 9-inch can be adapted to fit a wide range of vehicles, making it a popular choice for custom builds and restorations.
What are the Different Types of Ford 9-Inch Third Members?
Ford produced the 9-inch differential over many years, and variations exist across different model years and applications. Key differences often include housing styles (e.g., cast iron vs. nodular iron), axle flange styles, and the type of differential used (e.g., open differential, limited-slip differential, locking differential). Aftermarket manufacturers offer even more variations, further expanding the options available.
What are the Common Applications of a Ford 9-Inch Third Member?
The 9-inch's versatility leads to its use in a wide array of applications, including:
- Hot Rods and Custom Cars: Its strength and customization options make it a favorite for classic car restorations and high-performance builds.
- Muscle Cars: Many muscle car enthusiasts upgrade their original rear ends to a 9-inch for increased durability and performance.
- Off-Road Vehicles: Its robustness makes it well-suited for the stresses of off-road driving.
- Race Cars: In various racing disciplines, it provides the strength and adjustability needed to handle high power levels and aggressive driving styles.
How Much Does a Ford 9-Inch Third Member Cost?
The cost of a Ford 9-inch third member can vary widely depending on its condition, modifications, and whether it's a new or used unit. A used, unmodified unit can be relatively inexpensive, while a fully built and customized unit can cost significantly more.
Where Can I Find a Ford 9-Inch Third Member?
Used 9-inch units can be found at various junkyards, salvage yards, and online marketplaces. New and rebuilt units, as well as parts and components, are widely available from numerous automotive parts suppliers and specialized performance shops.
What are the Pros and Cons of Using a Ford 9-Inch Third Member?
Pros:
- Exceptional strength and durability
- Wide range of parts and upgrades available
- Relatively easy to work on and maintain
- Versatile and adaptable to many applications
Cons:
- Can be heavy compared to some other differentials
- Requires specific mounting hardware and potentially custom fabrication for some applications
- Can be expensive if extensively modified
This exploration of the 9-inch Ford third member provides a solid foundation for anyone considering this iconic differential. Remember to always research your specific application and choose the right components for your project's needs. The vast availability of information and parts makes the 9-inch a rewarding choice for those who want a strong, reliable, and highly customizable rear end.
