Bad pinion bearing?

I have a 2018 tacoma (SR5) and have been noticing a clunk when I shift into drive and when driving. It currently has 171k. The drive shaft has around 1/4 to 1/2 in rotational play and 1/8 inch or less up and down at the rear differential. I have heard no whining or grinding sounds from the rear differential. Most of the forums say I would hear a whining sound if it was the pinion bearing. Is my rear differential going out? Is it the pinion bearing? Is all of this my paranoia of my truck dying?
Any help is appreciated!

Edit: it appears to be less and 1/8 inch of play and the pinion seal is not leaking.

 

Have you driven through any deep water? Check your u-joints.

 

I see "air lockers" on your profile...
Wondering if this could be the pinion nut having come loose, assuming a regear was also part of it.
Have you noticed any noises or oddities when backing up?

 

good catch, always look first, where the human was last

 

There is a solid chance it is just a loose pinion nut. It was re-geared around 120k I believe. I also have not been driving in any deep water (I am way too timid) and I have only noticed a clunk when shifting into drive or reverse (and sometimes when driving from a stop) but no grinding or screeching sounds.

 

When you say rotational play you mean 1/4-1/2 of an inch?

 

I'd suggest discontinue driving it and have it looked at before something really goes wrong with it (not sure if you still have any warranties with the shop that did it, but maybe have them look at it if they're still around). Hopefully it's just that (a loose nut lol) and it can be retightened (perhaps they just forgot to stake the nut).