When you move the shift button the rear end shift actuator actually moves and preloads the shift mechanism, but can't overcome the engine load until you let off the gas and then it slaps it into gear.
Shifting from Hi to Lo when not under load (like on a flat straight away) will cause the gears to grind. That's why I just leave it in Hi when slowly rolling up to a traffic light and wait until I'm at a dead stop to shift it back to Lo.
You'll know when it happens! Just get out on a quiet road and practice a little, it's not hard to figure out what works for you.
Mike B
