I have a 2008 F250 that the tailgate has always been real easy to open and close until the other day I could not get it to latch so i slammed it and it did latch and it worked a few days but now it won't latch at all. I can open and close the latch with the tailgate down but nothing I do will make it latch in place. I've tried spraying with PB blaster it didn't help. Not sure if its out of adjustment or what. I'd appreciate any thoughts or ideas.

 

Take the cover off to get access to the locking mechanism; may be just a simple matter of cleaning it out and tightening stuff up. I had a nice mouse nest in my 2006 tailgate a few years back.

 

I figured it out. The pins the tailgate latches to got loose and slid back not letting it latch. I put them back in place and tightened them with a torx T50 now it works as good as ever.