To shift from 2H (4X2) or 4H (4X4 HIGH) to 4L (4X4 LOW):

WARNING: This page is about a different car, the 2018 Ford F-550 Super Duty, 2018 Ford F-450 Super Duty, 2018 Ford F-350 Super Duty, and 2018 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.

Bring the vehicle to a speed below 5 km/h (3 mph).
Shift the transmission to neutral.
Shift the transfer case to 4L (4X4 LOW).
If the transfer case shift lever does not move, or only partially moves, to the 4L (4X4 LOW) position, carry out a transfer case shift with the transmission in neutral and the vehicle rolling at a speed below 5 km/h (3 mph). This ensures the transfer case is fully engaged into 4L (4X4 LOW).