Shaking front end/Tie rod misery
 

Problem is as follows: Front end shakes like a bounce house between 30 and 54 mph. Left front tire showing dramatic tread wear, right front and both rears normal. Took it to local shop and told right lower (rear?) tie rod needs replacing + alignment etc. Got it home, jacked up each front wheel at the jack point on each lower a-frame and checked both sides myself.
Results: Left front wheel - solid, no play/slop. Right front wheel - 1/2" to 3/4" of loose play/slop at the steering rack end of the tie rod (the ball joint seems OK).
Is there an adjustment of some kind to be made either of the tie rod OR in the steering rack to take up that slack (or something inside the boot attached to the inner end of the tie rod that needs replacing/adjustment), or is this possibly a fluid pressure issue in the steering rack of some kind?
The truck is a 98 base model, 2wd, automatic tranny, 2.7 ltr 4 banger with 114,000 miles on it, no significant impacts to the front suspension, and no fluid leaks of any kind. I really need help on this one!