While changing the oil in my front diff, I found one single needle from a needle bearing stuck to the magnetic drain plug. I opened the cover expecting to find all kinds of damage but everything looks mint, like it did when it rolled out of the factory. I have no idea where the needle could have come from or how it got to the bottom of my pumpkin without causing any visible damage. It is hard to inspect the spider gears due to the rubicon locker, but from what I can see there is no damage in there either. I don't have a schematic of the locker assembly so i don't even know if there are needle bearings used internally. The closest needle bearings I can think of would be in the u-joints, but I can't see how one could find its way inside the pumpkin.
Any suggestions as to how this happened would be appreciated. Also I wouldn't mind hearing what some of the more experienced wrenchers have to say about what they would do in this situation.
Thanks.