Description
The ARB Air Locker Differential RD109 is a pneumatically operated locking differential for the Dana 44 rear axle, 35-spline, with ring-and-pinion gear ratios of 3.92 and numerically higher — designed to fit 1997–2006 Jeep Wrangler (TJ) in all submodels.
IMPORTANT: This listing is for the RD109, which covers the Dana 44 rear axle with 35-spline shafts and gear ratios of 3.92 and up. Buyers with a 3.73 or numerically lower ratio should see ARB RD147 (Dana 44, 35 SPL, 3.73 & Down). Buyers requiring 30-spline fitment should see RD116, and 33-spline buyers should see RD113. Additionally, ARB notes that performance application models do not suit any original equipment axle shafts — custom shafts to suit your specific axle assembly must be obtained if this is a performance build.
The ARB Air Locker is a selectable locking differential that delivers 100 percent traction on demand without affecting on-road drivability or driveline wear. When engaged, the Air Locker prevents the internal differential gears from rotating, locking both axle shafts directly to the ring gear so maximum traction is sent to both wheels simultaneously. When disengaged, the unit reverts to normal open-differential operation, preserving everyday handling and tire wear characteristics.
Engagement is pneumatically controlled via an in-cab activation switch. The Air Locker can be engaged or disengaged at any speed, allowing the driver to respond to changing terrain without stopping. The patented “timed” locking mechanism provides high-speed, reliable unlocking — a critical advantage when transitioning from technical terrain back to normal driving. Operation is handled entirely from the driver’s seat, requiring no manual hub locking or vehicle exit.
The Air Locker uses a two-piece steel differential housing with minimal moving parts for maximum long-term reliability. The seal is a steel-reinforced, elastomer-bonded annular design rated to handle extreme climatic temperature ranges. Each kit includes the Air Locker differential assembly, an in-cab activation switch, solenoid valve, air line, and bulkhead fitting. A separate air compressor is required for operation and is sold separately. ARB backs the RD109 with a 5-year warranty.
- Fitment: Dana 44 rear axle, 35-spline, gear ratio 3.92 and numerically higher — fits 1997–2006 Jeep Wrangler (TJ) in all submodels including SE, Sport, Sahara, X, Rubicon (2003–2006), Unlimited (2004–2006), Unlimited Rubicon (2005–2006), and 65th Anniversary Edition (2006)
- Selectable locking differential — 100% traction on demand with no effect on open-differential on-road behavior when disengaged
- Pneumatically activated from the driver’s seat via in-cab switch — engageable and disengageable at any speed
- Patented timed locking mechanism for high strength engagement and ultra-fast disengagement
- Two-piece steel housing — minimal moving parts for maximum reliability
- Steel-reinforced, elastomer-bonded annular seal rated for extreme temperature operation
- Kit includes: Air Locker differential, activation switch, solenoid valve, air line, and bulkhead fitting
- Air compressor required for operation — sold separately
- Note: Performance application models do not suit OE axle shafts — custom shafts required for performance builds
- 5-year ARB warranty
- Sold individually
| Part Number | RD109 |
| Axle | Dana 44 |
| Position | Rear |
| Spline Count | 35 |
| Shaft Diameter | 1.50 in |
| Gear Ratio | 3.92 and Up (numerically higher) |
| Activation | Pneumatic (air compressor required, sold separately) |
| Material | Steel |
| Color | Silver |
| Kit Contents | Air Locker differential, activation switch, solenoid valve, air line, bulkhead fitting |
| Warranty | 5 Years |
| Prop 65 | No |
The ARB RD109 is engineered for the Dana 44 rear axle with 35-spline shafts and ring-and-pinion ratios of 3.92 and numerically higher. It covers 1997–2006 Jeep Wrangler (TJ) across all factory submodels. Important distinction: buyers whose Dana 44 rear axle carries a ratio of 3.73 or lower (numerically) must use ARB RD147 — not this unit. Confirm your axle ratio before ordering.