@Elliott hopson
I own a 2004. To leave 4X4 AUTO and go to 4X4 HIGH involves depressing the "HIGH" button momentarily, at any time, moving or standing still. The "HIGH" light will immediately illuminate. DON'T do it on pavement!
To leave 4X4 AUTO and go to 4X4 LOW requires stand-still and depress and hold brake pedal while momentarily depressing 4X4 LOW button. It sometimes takes a short time to engage, especially if not used ever. During engagement, the "LOW" light may flash until it engages, during which time the brake pedal must remain depressed, or it will back out.
To go from 4X4 HIGH back to "AUTO", simply momentarily depress the "AUTO" button, at any time, standing or moving. To go from 4X4 LOW back to either HIGH or AUTO, the vehicle must be standing vstill, and the brake pedal depressed. 4X4 AUTO is the position used for most all normal driving conditions.
The front wheels are driven by an "Electronic Clutch" which allows HIGH to be engaged simply by pushing the button. LOW involves actually moving parts within the Transfer Case, driven by an electric motor, a process which might take a number of seconds to accomplish. AUTO applies the clutch only when wheel slip is detected, and on certain road surfaces where frequent wheel slip can occur, like packed mud with soft spots here and there, the clutch may turn on and off rapidly resulting in a quite uncomfortable, noisy jarring. If that happens, simply depress 4X4 HIGH. DON'T FORGET to go back to 4X4 AUTO before going back on pavement! imp