Ever since I crashed my truck, I always leave it in Auto4. It would have saved me if I had pushed the fricken button. OH, and the fastest way to shift out of 4low is to stop, put it into neutral and then push the button. Should take just wait a couple seconds.

 

werd be parked and put it in N
and then you'll hear a CLANNK!!!

 

if you are rolling to fast, then it will not shift out of 4lo. like the guys said before, stopping 1st, put it into neutral, then push 2hi.

i think the problem is in your push buttons. i had the same problem. it is common in the 99's. might want to get a new one. i think they are like $50. my truck would always engage into 4lo by itself because of this faulty switch