Air Locker Differential Dana 70/80The Ultimate Towing Traction: Lock Your 1 Ton Axle for Serious Duty. When you are piloting a Ford F 350 Super Duty or a heavy duty Ram, you are relying on massive torque to move massive weight. Unfortunately, the factory limited slip differentials in these Dana 70 and Dana 80 rear ends often wear out or fail to provide true two wheel drive when you are stuck in mud with a loaded gooseneck. The ARB RD174 is the solution: a competition grade locking