Lower Unit Blues

O.K guys, heres one for ya. Upon returning from Dale Hollow last week, Out of curiosity I thought I would check the gear oil in my 2 week old lower unit. The second I got the lower screw out enough for the gear oil to start to flow, a piece of metal the size of my pinky fingernail came out. This lower unit is brand new, gearcase, gears, prop shaft, everything! Needless to say I freaked! Because this is the 4th time this has happened in two years. on the other occasions I have had the unit repuilt by the best in the biz, and being that the last time it happened they ordered a whole new unit, I know it isn't my mechanic. I'd sure like to know what is going on with the dang thing! If you know me at all, you know I baby my boat. I spend a lot of time and money on upkeep. I know how to operate a bass boat. I always wait for the rpm's to drop to 900-1000 before shifting into gear, I don't have a hot foot, I never launch the boat over wakes and never over rev it. I just thought someone watching the board may have some similar experience because this is killing me!