The replacement 4x4 Transfer Case Lower shift linkage arm allows your F-150, F-250, F-350 or Ford Bronco to shift in and out of 4WD mode. This part acts as like a middle-man that tells your transfer case on what desired mode the vehicle is being shifted into. Over time, the factory transfer case linkage arm becomes stiff or gets stucked which results into the part breaking or not being able to shift the vehicle anymore
If you are having a hard time shifting your vehicle in and out of 4WD mode then you may have a problem with this part and it is advisable to replace your transfer case shift linkage arm once stiffness of shifting in and out of 4WD mode is experienced to prevent it from snapping off and cause more problems while you are driving.