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

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.

With the vehicle stopped engage the hublocks to the locked position, making sure both indicator arrows are aligned.
Shift the transfer case to 4H (4X4 HIGH) with the vehicle rolling at a speed below 5 km/h (3 mph).