I have a 2002 Ford Ranger 4.0L 4x4 and sometimes when I try to engage four wheel drive it doesn't want to go in. It makes a clicking sound and then sometimes it slams in. Yesterday it seemed like it went half in and then i couldn't get it back to 2WD and it slammed out of 4WD. What could this be? Im pretty sure I still have my warranty that I am paying for that covers transmission/drivetrain. Is it possible that this would cover the problem?