Ok so i bought a a truck about two months ago and it has a 4x4 on the floor and it worked at first but now its not working and the shifter has always been really hard to shift. This is my first truck so i dont really now what to look for thanks for any help

 

Check to see if your transfer case has any fluid in it and make sure its the correct fluid should be the Mercon 5 transmission fluid same as you use in your transmission next see if any of the linkage has come undone or bound up somehow under your truck.