My 02 f150 4x4 has 40,000 mls, put new tires and shocks on in dec. of 2010. Also had alignment done. Now I have alot of side to side wander. Been to 2 other shops front end is tight, tire shop replaced all 4 tires again with no help. Could it be the gear box at 40m?

 

Find out what the caster and camber readings are vs spec. Are they in spec.
It could be the tire make and version as well. If so replacing them with the same won't fix it.
Check for broken anti roll (sway bar) links.
Steering box to frame tightness.
Steering linkage.
Is there any play in the steering wheel?
Could be the power steering response.
Check these out yourself. You have to many shops involved as it is.
Lots of possibilities and even more than one.
Funny none is finding any issue!
Good luck.

 

any good shop could tell you in 15 minutes what is loose. if not ball joint wear, then could be tie rod ends, steering arm anchor to the frame (idler arm bushing)... assuming the alignemnts is good. Jack up one tire 2 inches off the gound with a jack under hte a-frame. grab that tire and pull/ push it left to right as in turning. have your buddy lay under radiator and see what is moving and what is stationary.