Knocking from the front of my truck.

[TurboedMJ]

I've got a knocking coming from the front of my truck. It only does it when going over bumps or turning. I took the passenger side wheel off and spun the hub and I could a very slight knock when I changed the direction the hub was spinning. Before I tear everything apart, is it likely that my wheel bearings are going out? It first started knocking about 2 weeks ago on the passenger side and just started doing on the driver's side. 

[Pete M]

jack up the tire, put your hands at the top and bottom and shake hard (alternating in and out with your hands).  does it move?  now put your hands at the left and right and shake hard.  does it move?  if you push in and yank out on the tire with your hands in unison, does it move?  then reach in and shake the axle shaft.  does it move?  try rotating it.  how about now?  if you rotate the tire does the axle shaft move exactly together with the tire?

[gogmorgo]

A bit of a clunk when changing direction of a wheel is pretty normal. Usually it’s just the sum of all the lash in the differential, totally normal. Although it doesn’t hurt to check the u-joint in the axle shaft, hold the wheel end steady and try to turn the axle shaft, there should be no play in the ujoint. 

Wheel bearings don’t usually thunk when they fail. They’ll make a bit of a grinding noise, won’t feel like they roll smoothly, and like Pete says they’ll have play. Play in the wheel bearing will be a wiggle in all directions, you’ll see the wheel move but the steering knuckle stays put. Wiggle only in the top and/or bottom is going to be ball joints, the steering knuckle will be moving. Left/right is going to be in the steering somewhere.

 

I would also look at sway bar and end links. And both ends of the track bar. And the shocks. And control arms. And make sure the bottom end of the coil springs hasn’t snapped off. 
Basically look at everything in the front end. Its really tough to diagnose a sound over the internet without more details. Maybe about handling, any shakes or vibrations. 
Definitely look at where the track bar bolts to the axle, make sure it doesn’t move around. It might help to get someone to turn the steering wheel back and forth, just enough to slightly turn the wheels, and check for any signs of play in any of the steering or suspension pivot points.