On my way to a job interview this afternoon I hit a rather large crack on the 101. I heard something rattling under the truck and checked the mirror just in time to see it disappear under the car behind me.
Hmm... kinda "L" shaped, maybe 5-6 inches long, black and plastic or metallic... nahh, no idea what that was...
A few miles later and BAM! It was the damn oil breather cap and tube!

Anyway, now I need another one. Unless someone has a suggestion for an aftermarket replacement.