Chorleychappie

Hi, Changing the oil on my 2004 X5 4.8is today I hit a bit of a problem. When I removed the oil carttridge from the its position 3 items fell into the drain pan I was using, One is a thimble sized and shaped metal object tha't has slits in the sides, the second was a spring approx 1" long and the third was a small pice of black castellated plastic with 3 turrets.. It looks veru much like the spring fits into the thinble type object with the plactic piece then sitting on top but I havnt got a clue what it is or why its fell out and most importantly I guess is what wll the effects be? I have expanded views of the oil pump off the local BMW dealer but these parts arent identified anywhere on there. Can anyone help? I did find a thread on another forum 'roadrunner' where someone had posted the same dilema but they hadnt had a reply. Thanks in advance