As the previous post.... yes, you gotta have all three.. also I have noticed sometimes if you are stuck on a hill it will not switch out. Try reversing a bit, forward, nuetral, and try it again. Switch through 4 low, then to 4 high, then 2wd if it comes out. Sometimes going from 4low to 2wd won't kick it out right. I have had mine stick on occasion but it usually pops out with variation of the above methods. Good luck!