I have this S-10 1999, 4.3lt. 4 wheel drive which is giving me a hard time to reset in 2wd from 4 lo of 4 hi. I tried putting in reverse and forward as many suggested but sor far the only thing that works is to fiddle around between the 3 buttons and eventually it goes back in 2 wd. What could go be wrong with it. Is it a motor or a solonoid ? What is the mechanism of this system ? Is this a recurring problem with chevy trucks ?