Magnet found in front differential
 

I was changing the front axles on my 01 Tracker and the circlip broke off. I drained the gear oil and used a magnet to try and fish out the old clip but instead I came out with a 3/8" x 2" magnet and some sort of a ribbed plug about the same diameter. Any idea where these go?

pics
put the magnet at the bottom of the diff cover away from the crown and allow it to catch metal debris