Hard shifting 4500. Input shaft play. What to do now?

[The3rdAmigo]

Not the usual suspects. Bear with me, kinda long...

Bought the unbombed truck with 140K, PO said a stock clutch was installed by dealer at 138K. I put on the stuff in my sig. Now at 152K with some towing behind it, I find it hard to get in gear after being in neutral, engine running, clutch engaged- had to shift into 3rd or 4th to get 2nd or rev. Being skeptical if a clutch was really installed, I tear it down (as opposed to just throwing a $300 hydraulic system at it to see if it fixes it).

Everything looks excellent clutch wise (Like it was recently installed):
Pilot and throwout in great shape.
Fork and pivots good.
Flywheel- a few heat marks.
Clutch disk- no springs broken/ cracked, rivets good, and you can still see some of the ink marks on the disk, < .020 runout.
PP- no springs broken, Tines even
Clutch housing- < .015 bore runout, < .002 face runout.


The issue- Input shaft of the 4500 moves side to side. Bad thing in a tapered roller bearing situation. I can push the input shaft over and hit the bearing housing snout with it.

What now? Throw a new bearing on the input shaft and see what happens? Machine down the input retainer? Tear down the rear of the tranny and check endplay? I'm at a loss as to the first cost effective thing to do, being new to 4500's, but not trannys in general. Any help/ advice is appreciated.