Hey guys, I'm sure this might sound like a stupid question to a lot of you so I apologize in advance. I have a 93 ford explorer sport 4x4. I am curious exactly what the difference is between 4x4 high and low? Also, When would be the appropriate time to switch into 4x4 high and low. Should I be at a complete stop before switching into both high and low to avoid any damage done?? I have heard 4x4 low is for speeds up to 30 mph and 4x4 high is for any speeds (normal). Is this correct? Any help would be appreciated. Thanks for any help.