ELocker compatible with Dana 44 - 30 Spline Axles Fits 3.73 & Numerically Lower Gear Ratio The ELocker is an electronic, selectable differential designed for drivers that need traction on-demand. At the flip of a dash switch, drivers can go from open to 100-percent locked. A second flip of the switch deactivates the unit to resume normal driving. The ELocker is the most reliable on-demand differential, featuring selectable operation and net-forged gears for added strength.