I was driving to my local auto parts store today so I could change my fluids in my truck. I just bought it ('02 2500 HO) about a month ago and recently I heard a grinding noise that sounds like its coming from the back. I was going to inspect the rear diff. Anyway, On the way to the store, I heard a strange pop under the hood. I showed up to the store with coolant pouring out of my truck and saw that it looked like it was coming from the bottom of the water pump. It all seemed pretty obvious that I needed a new pump except that I found four small steel pins (about 5/32 diameter and 1/2 in. long) under the water pump on top of the gear housing. Any ideas as to what happenned? Maybe the pins were already there. I don't know. If anyone has any ideas I would appreciate it.