Loose Spark Plug

Doing my 60k maintenance a little late at 70k and found the passenger side middle spark plug able to be loosened by hand with signs of oil / combustion passing into coil area. Truck ran fine before and after plug change just not sure how concerned I should be if that cylinder was running at low compression for 70k miles.

I am a little disappointed by this from Toyota as well as the large metal pieces I found in my front differential while charging the fluid, couple pics of that too.

 

Yea this seems to be quite a common issue

 

Ouch, consider front diff broken in!

 

You can’t do anything about it now, what’s done is done. Do you inspect the boot on the coil? If it fails no biggie, easy fix.
As far as the diff, I had a piece of a side gear tooth come out of my Legacy GT at about 90k. I sold it with 189k and it was still fine.