How much play (if any) is acceptable on the ball joints?
Vehicle is a '98 2WD.

I lifted the front yesterday to check movement.
Top Ball Joints: I can move the top of the tires in-out just slightly ~ .125"
Lower Ball Joints: Up and down movement is about a ~ .25" on drive side and ~ .125" on the passenger side.

Obviously they're showing signs if wear.
I just bought new tires; 'HIGHLY' recommend changing ASAP or can I push it a bit longer without major concern?

 

If you can move them by hand, think how much they're moving with 6000+lbs of truck leaning on them in a corner. Pony up for good 1's too, if you go cheap you'll be replacing again soon.

 

You are way past where replacement is necessary with 1/8" and 1/4" of slop.

Get them changed now.

 

Thats alot of play for ball joints. If you can "feel" movement in the joint, its life is not long as it has worn past the hardened surfaces in the joint and will wear out fast. It messes your alignment and will chew up your tires.

 

You're due. That's a lot of play.

 

MOOG's I believe are still USA made. Don't get the Chinese junk.