The ARB Dana 44 air locker RD109 for your 35 spline axle for 3.92 & Up gear ratios, can instantly lock differentials and allow you to tackle the toughest off-road terrain. The world's best traction aid, ARB Air Lockers keep you moving in all conditions. The Dana 44 ARB® #RD109 air locker is only engaged when needed, it can be installed in BOTH the front and rear axles, with separate switches independently controlling the RD109 air locker from within your Jeep.