Eaton HO52 pinion bearing slop

[JMD]

Hey all,
I replaced the pinion seal on my HO52 rear axle following the instructions I took from this site. Before I took the pinion nut off I recorded exactly how many threads were showing and marked were the nut was in relation to the pinion. I put everything back together and everything seemed tight. No slop in the yoke so I figured I was good to go. At this point I only had a rolling chassis.

Today, now 6 months later I noticed that there is a lot of slop in the pinion. I can move the yoke up and down a considerable amount. It's still a rolling chassis (no driveshafts) so I don't see how it could have been worn at all from just rolling back and forth in my shop.

What's my best course of action here? Do I just tighten the nut until there's no play in the yoke?