Rear Diff Drain plug - magnet fell off

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Hey everyone,

So I finally drained and filled my diffs. Used Synthetic 75w90 for both.

When I drained the rear diff, I got the plug out, but it basically fell apart in my hand. The magnet broke off of the plug (there is still a little piece of magnet in the plug). Any ideas on where I can find a replacement thats not $40? (Dealer price local to me...)

Interestingly enough, the fluid was pretty dark, but there was next to no sludge or filings on the rear plug. The front plug was a different story, there was about 1/4" of black gunk stuck all the way around the magnet. No recognizable filings, but more material than I wanted to see on it. It has been about 120k kms since my last drain and fill on the diffs though, so I suppose that makes sense. I won't let it go that long next time.