ARB GM 14-Bolt Full-Float Air Locker Differential - 10.5", RD234
RD234
The ARB GM 14-Bolt 10.5" Full-Float Air Locker Differential is a selectable locking differential designed for heavy-duty GM 14-Bolt rear axles upgraded to 40-spline axle shafts. Built for maximum traction and driver control, this air-operated locker allows both rear axle shafts to be locked together at the flip of a switch, providing dependable traction through rocks, mud, steep climbs, and demanding off-road terrain. It's an excellent choice for rock crawlers, rock bouncers, Ultra4 race vehicles, and custom one-ton axle builds running large tires and high-torque drivetrains.
When activated, compressed air engages the internal locking mechanism, mechanically connecting both axle shafts for fully locked traction. Its high-strength two-piece steel carrier, precision-machined locking components, and reinforced annular air seal are engineered to withstand demanding drivetrain loads. Designed for compatible GM 10.5" 14-Bolt full-float housings, this 40-spline locker supports multiple gear ratios, with thick high-offset ring gears required for 4.56-and-numerically-higher applications.
Includes:
- (1) ARB GM 14-Bolt 10.5" 40-Spline Air Locker Differential Assembly
- (1) Dash-Mounted Activation Switch
- (1) Air Solenoid Valve
- Air Line
- Bulkhead Fitting
Important:
- A compatible ARB Air Compressor is required for operation and is sold separately.
- Requires 40-spline axle shafts. Factory 30-spline GM 14-Bolt axle shafts are not compatible.
- Gear ratios of 4.56 and numerically higher require a compatible thick, high-offset ring gear.
- Custom axle shafts must be selected to match the housing width, hub configuration, and differential spline requirements.
Specifications
| Manufacturer | ARB |
|---|---|
| Part Number | RD234 |
| Product Type | Selectable Air Locking Differential |
| Axle Platform | GM 10.5" 14-Bolt Full-Float |
| Ring Gear Diameter | 10.50" |
| Axle Position | Rear |
| Axle Spline Count | 40-Spline |
| Gear Ratio Compatibility | All Ratios with Correct Ring Gear Configuration |
| Gear Set Type | Standard Ring Gear for Compatible Ratios; Thick High-Offset Ring Gear for 4.56 & Up |
| Carrier Compatibility | GM 10.5" 14-Bolt Full-Float Housing - 40-Spline Configuration |
| Differential Operation | Selectable Open / Fully Locked |
| Engagement Type | Pneumatic / Compressed Air |
| Carrier Construction | High-Strength Two-Piece Steel Case |
| Locking Mechanism | Air-Actuated Mechanical Locking Gear |
| Installation Type | Replaces Factory Differential Carrier |
| Primary Application | GM 14-Bolt 40-Spline Rock Crawlers, Rock Bouncers, Ultra4 Racing & Heavy-Duty Off-Road Builds |
| Required Components | 40-Spline Axle Shafts, Compatible Air Compressor, Air Supply, Ring Gear & Differential Installation Components |
| Known Incompatibilities | Factory 30-Spline Axle Shafts; GM 9.5" Semi-Float 14-Bolt; Incompatible Ring Gear or Housing Configurations |
| Quantity | One Selectable Air Locker Assembly |
Fitment
Designed for compatible GM 10.5" 14-Bolt full-float rear axle housings converted to 40-spline axle shafts. This is an axle-specific performance differential rather than a direct replacement for factory 30-spline truck applications.
| Make | Model | Year Range | Axle Application |
|---|---|---|---|
| Chevrolet | K30 / V30 1-Ton 4WD | 1977–1991 | GM 10.5" 14-Bolt Full-Float Rear - 40-Spline Conversion |
| Chevrolet | C30 / C3500 | Various | GM 10.5" 14-Bolt Full-Float Rear - Verify Housing |
| Chevrolet | K3500 | 1988–2000 | GM 10.5" 14-Bolt Full-Float Rear - Verify Housing |
| Chevrolet | Silverado 2500 / 2500 HD | Various | GM 10.5" 14-Bolt Full-Float Rear - Equipped Models Only |
| Chevrolet | Silverado 3500 / 3500 HD | Various | GM 10.5" 14-Bolt Full-Float Rear - Equipped Models Only |
| GMC | K3500 / V3500 | Various | GM 10.5" 14-Bolt Full-Float Rear - Verify Housing |
| GMC | Sierra 2500 / 2500 HD | Various | GM 10.5" 14-Bolt Full-Float Rear - Equipped Models Only |
| GMC | Sierra 3500 / 3500 HD | Various | GM 10.5" 14-Bolt Full-Float Rear - Equipped Models Only |
| Custom Fabrication | Rock Crawlers, Rock Bouncers & Tube Chassis Buggies | All | GM 10.5" 14-Bolt Full-Float Rear - 40-Spline Build |
Fitment Notes:
- Fits compatible GM 10.5" 14-Bolt full-float rear differential housings
- Requires 40-spline axle shafts
- Factory 30-spline axle shafts are not compatible
- Gear ratios of 4.56 and numerically higher require a compatible thick, high-offset ring gear
- Not compatible with GM 9.5" semi-float 14-Bolt differentials
- Not intended for GM 11.5" AAM rear axle applications unless separately confirmed
- Compatible custom axle shafts must match the housing width, spline engagement, and hub configuration
- Requires a compatible compressed air supply for locker engagement
- ARB air compressor sold separately
- Verify ring gear mounting configuration, carrier bearing dimensions, axle shaft spline count, and housing type before ordering
- Professional differential installation and air system routing are recommended
Builder Note: The GM 14-Bolt is a popular platform for heavy-duty off-road builds because of its large ring gear, full-float design, and aftermarket support. Converting to 40-spline axle shafts is a significant upgrade, but the locker, shafts, ring gear, and housing must all be matched correctly. For custom axle builds, confirm the complete drivetrain package before ordering individual components.
FAQ
What does an ARB GM 14-Bolt Air Locker do?
The ARB Air Locker is a selectable locking differential that allows the driver to switch between normal open differential operation and fully locked traction. When engaged, compressed air activates the internal locking mechanism, forcing both rear axle shafts to rotate together for improved traction in demanding off-road conditions.
Will this Air Locker fit my factory GM 14-Bolt axle?
This locker is designed for compatible GM 10.5" 14-Bolt full-float rear axle housings using 40-spline shafts. Most factory 14-Bolt axles use 30-spline shafts, so a compatible 40-spline axle conversion is required.
Can I reuse my factory 30-spline axle shafts?
No. This locker requires 40-spline axle shafts. Factory 30-spline shafts will not engage the differential side gears and must be replaced with compatible 40-spline components.
What gear ratios work with this GM 14-Bolt Air Locker?
The supplied specifications identify compatibility across GM 10.5" 14-Bolt gear ratios. Ratios of 4.56 and numerically higher require a compatible thick, high-offset ring gear to maintain correct ring gear positioning.
What is the difference between a 30-spline and 40-spline GM 14-Bolt axle?
A 40-spline axle configuration generally uses larger, stronger axle shaft components than the factory 30-spline arrangement. This provides additional strength for large tires, high-horsepower engines, and demanding off-road use. Converting to 40-spline shafts requires matching differential and axle components.
Does the ARB Air Locker stay locked all the time?
No. The locker operates as a conventional open differential when disengaged. The driver activates it when additional traction is required and switches it off when normal differential operation is preferred.
How is an ARB Air Locker different from a Grizzly Locker or spool?
An ARB Air Locker provides selectable locking through compressed air. A Grizzly Locker is an automatic mechanical locker that engages and disengages according to driving conditions. A full spool permanently locks both axle shafts together. The ARB allows the driver to choose when the axle is locked.
Does this locker require an ARB air compressor?
Yes. A compatible ARB air compressor and air supply system are required to activate the locking mechanism. The compressor is sold separately.
Is this locker suitable for rock bouncing and Ultra4 racing?
Yes. The 40-spline configuration is intended for high-strength off-road axle builds, including rock crawlers, rock bouncers, and Ultra4-style competition vehicles. Correct axle shaft selection, ring gear compatibility, and differential setup are essential for reliability under extreme loads.
Can I use this Air Locker in a custom fabricated 14-Bolt axle?
Yes, provided the fabricated housing uses compatible GM 10.5" 14-Bolt differential dimensions and the correct 40-spline axle shafts. Verify carrier bearings, ring gear mounting, shaft engagement, and housing clearance before installation.
Does this locker include axle shafts or ring and pinion gears?
No. The supplied kit includes the Air Locker differential assembly and air activation components. Axle shafts, ring and pinion gears, carrier bearings, and other differential installation components are sold separately unless otherwise specified.
Can this locker be installed during a gear ratio change?
Yes. Installing the Air Locker during a re-gear is practical because the original differential carrier is already being removed. Proper carrier preload, ring gear backlash, and tooth contact pattern must be established during installation.
