So I just received the call from my dealer, I took my truck back because I noticed a hard shift from drive to reverse, and also from 1-2. Well after three days, they just called to tell to me it was a bad cam phaser? What in the heck is a cam phaser and would that be what would make it shift hard? Thanks!

 

the cam phaser is how it adjusts the timing of the valve opening - not sure how it would cause hard shifting, usually they just make weird noises when they go out