4wheel drive problem, S10

I have a 1995 S10 and I can not get it to disengage from 4 wheel drive. Any idea what would cause this problem?

Is this push button or manual shift?
jack up both front tires and try to spin front shaft. If shaft spins but front tires turn also I would replace vaccume hub switch. www.s104x4.com click on tech articles for vaccume diagrams.
If you cant spin front shaft and you have push button 4x4 could be shifter decoder motor. Check for stored trouble codes for 4x4 system.