Tight the locking nut until moderately tight, then back off 1/4 turn, or until the wheel spins freely and there is no play in the wheel.

Grab the wheel at 12 o'clock and 6 o'clock, if you can feel the wheel wobbling slightly, it's too loose...

"Does this part need to be in there?"

1996 Dodge 1500 single cab / short bed, 5.9 4x4; 2" lift (springs not blocks), C.A.I and more mods to come.