Hi all, I am actually a Nissan Frontier owner and have been on ClubFrontier.org for a long time. However, my dad has a 2005 Fx4 F150. His 4wd is no longer working and this problem has us stumped! When the selector switch is turned the dash light "4 Hi/4Lo" does illuminate however it does not engage. You can feel it shutter slightly when u put it in 4lo and it shifts into a really low gear but no 4wd. I got underneath of it and the driveshaft to the front diff. does turn......