Metal shaving in rear diff oil

First time doing the rear diff myself, but have had it done before at 32k miles. It's now 100k, so way overdue. The oil that came out looked as expected, dirty but with a red hue. Drain plug had the expected amount of gunk stuck to the magnet, nothing excessive in my opinion. But, I found this single metal saying, about an inch long in the old oil? I read this can be expected on the very first diff oil change, but with 100k miles, I'm not sure? Not having any issues otherwise... Any ideas? Should I be concerned at all?

6spd, Off-road...

 

I wouldn't be concerned. That almost looks like a piece of leftover thread cutting material. Concern would be if you had lots of small pieces in the oil, indicating a chipped/damaged area that is getting worse with use. A little metallic slurry is normal on a drain bolt, too. It just means the gears are wearing as all gears do. I'd toss that thing, drive it 15 or so k, and recheck if it makes you feel better.

 

I would agree that looks like a chip from manufacturing, I can't imagine how a gear or bearing damage looking like that. I'd keep driving it with no concern, it probably just didn't come out in the first change.

 

Thanks for the confirmation! That's basically where I landed as well, but wanted some reassurance...

 

And it never got chomped on by the gears

 

100% normal.
Nothing to worry about.

While it could be prevented from the factory. It would add time to the machining process.
The differential is not a pressurized system. Any large machining chips will settle at the bottom of the differential and mostly be held in place by the magnet on the drain plug. Big chips like that will never reach gears.

Again, nothing at all to worry about. Those turning chips can be found in most differentials on these trucks.
Some just never “break off” and make it to the drain. But they are in there.

 

IMO, it was just waiting at the bottom of the diff but did not get flushed out with the first oil change.

 

When I did mine I had a piece of metal the shape of the drill bit end stuck on my drain plug. It was about a half inch in diameter. Toyota's rear-end manufacturer is a little lax in making sure the machining debris is cleaned out.

 

Yep, machining debris. Due to the shape and size it probably couldn’t get close enough to the magnet to stick. Good to get it out but probably completely harmless anyway.

 

Thanks!! I'm definitely feeling reassured at this point. Need to do my front diff, transfer case and serpentine belt next!