knuckle must come out...when you remove the 4 bolts holding the ball joint on it doesn't just drop out the bottom, it slides out the end of the lower control arm. if you crawl under your truck and look you will know what I'm talking about. the knuckle comes off with 3 good whacks of a hammer. I had mine off a few times, 20 minutes after the wheels were off I had both knuckles on the ground. make sure you take the little locking clip off the end of the axle spline behind the cap on the drive flange...it can be easily missed.