It depends a lot on the type of vibration you are suffering. If it is a type of slapping that you feel and hear in the wheel itself no matter speed, etc then it is probably the intermittent steering shaft, they are known for failure. You CAN take it out and grease it but that is a temp fix while replacing it would be best.
As mentioned above, it could also be the ball joints. (more commonly the lower than the upper.) To check the ball joints, raise the truck as mentioned above and put a large pry bar or tank bar under the lower control arm and pry upward on it, if you see ANY separation or independent movement from the ball joint in the control arm then it needs replaced.
To check the hub bearing while it is in the air, grab the tire at 6 & 12 o'clock and try to move the tire up and down. If there is ANY place up and down at all then the hub baring is going/gone bad and needs replaced. (The tire will be able to move side to side easily if both sides of the truck are off the ground.)
To Check the idler and pitman arms, with the wheels on the ground and the engine running in park, have someone turn the steering wheel side to side while you lay under the front of the truck and watch the steering linkage for play. If there is any play at all up and down in any of the joints at either end of either the pitman or idler arms then I would recommend replacing both units at the same time.