When is shifting in and out of 4WD/AWD required?

Shifting in and out of 4WD is typically required with part-time 4WD systems. These systems are designed for use primarily on off-road or slippery surfaces and require the driver to manually engage or disengage the 4WD mode depending on the driving conditions. In part-time systems, using 4WD on dry pavement can cause drivetrain binding due to the difference in wheel speeds, which can result in damage over time.

On the other hand, full-time 4WD systems are equipped to operate in 4WD mode continuously without requiring manual shifting, providing a seamless transition as conditions change. On-demand 4WD systems automatically switch between 2WD and 4WD as needed, so the driver does not have to intervene. Meanwhile, AWD systems are designed to provide power to all wheels all the time without the need for shifting. Thus, the necessity for manual shifting is a distinguishing characteristic of part-time 4WD systems.