2005 4runner question if you can help

 my mother has this toyota four runner engaged in four wheel drive that will not disengage . 

i've not yet touched the vehicle and no trust for the dealers mechanic. 

 this mechanism is a push of the button away you go device.  i'd never own one but there it is stuck engaged.  rarely if ever used for that purpose and only driven about ten miles a day. 

 i'd shrug it off but riding in it knowing the damage being done to the front end (all roads are paved now a days ) .   other than suggesting them to stay off the pavement, i could only think of you kind folks. 

    so let it rip. if you can.  i'm visiting for about a week and hope to at least get them to understand what needs to be done.        it's a 2005 toyota four runner eight cylinder.  other than that i know nothing about it.    again thanks in advance.