One of my Toys is an 85 mini truck. I rebuilt my knuckles and replaced the inner axle oil seals about a year ago. I have about 200 miles on it since the rebuild. All of a sudden I started hearing a click in the front diff. I took everything apart thinking I had broken my locker or ring teeth or something. When I inspected the diff, there was nothing wrong. I fished around in the axle housing, and found this ring cap thing sitting below the drain plug. I have no idea what it is. When I look in each end of the axle, on one side, about an inch or so past the oil seal on one side is a similar ring, and the other side it is missing. Is this something that is pressed or fixed into the axle housing? Is it a guide for the axles? I'm thinking when I put my axles back in, I must have knocked it loose or something and over the 200 miles it eventually worked it's way down the housing tube and into the diff. If it is something that is supposed to be fixed or pressed into the housing, how do I get it back in it's place? Thanks!