Engine/Transmission (1998.5 - 2002) aluminum in oil pan?????

[TShively]

I was helping a friend replace his engine oil pan gasket and when we were cleaning out the pan we found a fair amount of aluminum shavings in the bottom (about half the size of your thumb nail). We rolled the engine around and from what we can see of the pistons they look fine. I was thinking maybe a thrust washer or bolt came loose from the front cover? Due to the boss that the oil drain plug threads through we are thinking that it's been in there a while, plus that would catch any bolts or other debris from coming out at oil changes. Any input would be greatly appreciated!!