The world famous ARB Air Locker!

ARB developed a truly selectable locking differential over 30 years ago. This innovative design applies Air pressure to a bonded seal which drives a clutched gear onto a splined gear. This locks the spider gears from turning and the result is a 100% locked axle. A flip of the switch releases the air pressure and allows the return springs to slide the clutch gear off of the splined gear returning the differential to its original unlocked state.

The RD121 will fit the following Toyota 8″ Clamshell front differentials with 3.73:1 and down ratios (higher gear ratios).