Wow! An incredible amount of misinformation here. Assuming you're asking about shifting between two-wheel drive (H2) and four-wheel drive (H4), my owners manual (pg. 188) says shifting from H2 to H4 can be done at any speed under 62mph. You don't need to stop, shift into neutral, or even reduce pressure on the gas pedal. The reverse (H4 to H2) can be done at any speed. If the vehicle fails to shift (indicator blinks), gently accelerate or decelerate while operating the switch again.
This may be slightly different with other model years. When in doubt, read the owners manual.
If I do shift while moving it is never with any throttle or force on the tires. Next time your on a steep hill in 4x4 take it out while going down and see what happens.