ARB Ford 9" Custom Air Locker Differential
RD99
The ARB Ford 9" Custom Air Locker Differential is a selectable, air-operated locker designed for performance and custom Ford 9" axle builds. When activated, the Air Locker locks both axle shafts together so both wheels turn at the same speed for maximum available traction. Switch it off and the differential returns to open operation for easier steering and maneuverability when full lockup is not needed.
This version is intended for custom axle assemblies rather than a direct factory Ford 9" replacement. Custom axle shafts are required and must be matched to the housing, spline configuration, and complete axle build. Pneumatic controls are included with the locker, while an ARB air compressor is required separately to operate the system.
Includes:
- (1) ARB Ford 9" Custom Air Locker Differential
- Dash Activation Switch
- Solenoid Valve
- Air Line
- Bulkhead Fitting
Note:
- ARB air compressor required for operation and sold separately.
- Custom axle shafts are required and must be matched to the housing, spline count, and application.
- This performance application is not designed to accept original-equipment axle shafts.
Specifications
| Specification | Details |
|---|---|
| Manufacturer | ARB |
| Product Type | Selectable Locker Differential |
| Axle Platform | Ford 9" |
| Application | Custom / Performance Axle Builds |
| Locker Type | Selectable Air Locker |
| Activation | Pneumatic |
| Unlocked Operation | Open Differential |
| Carrier Design | Two-Piece |
| Material | Steel |
| Air Compressor | Required – Sold Separately |
| Axle Shafts | Custom Shafts Required |
Fitment
| Axle Platform | Application |
|---|---|
| Ford 9" | Custom / Performance Axle Builds |
Fitment Notes:
- Designed for aftermarket housings, custom third members, and performance axle assemblies.
- Does not accept original-equipment axle shafts in the performance configuration described here.
- Custom axle shafts must be matched to the housing, locker spline configuration, and overall axle build.
- Some alternate axle spline configurations may require builder-level modification.
- Verify the exact Air Locker configuration and axle spline requirements before ordering shafts or assembling the third member.
FAQ
How does the ARB Ford 9" Air Locker work?
The Air Locker uses compressed air to engage the locking mechanism inside the differential. When engaged, both axle shafts are locked together. When disengaged, the differential operates as an open differential.
Does this Air Locker require an air compressor?
Yes. A compatible ARB air compressor is required to operate the locker and is sold separately.
Can I use factory Ford 9" axle shafts?
No. The performance application described here does not accept original-equipment axle shafts. Custom axle shafts must be ordered for the specific housing and locker configuration.
Is this a direct replacement locker for a factory Ford 9" axle?
No. This version is intended for custom and performance Ford 9" axle builds using compatible aftermarket components and custom axle shafts.
What should I verify before ordering this Air Locker?
Confirm the Ford 9" third-member configuration, axle shaft spline requirements, housing dimensions, and the custom axle shafts required for the complete assembly.