Clicking stopped?!help)

[Robert W Obrien <rwo@u.arizona.edu>]

Thanks everyone for the replies. I had just checked my mail and was
rolling home to investigate the speedometer, thinking, "damn, what an
annoying noise" when, at around 50 mph on a busy road...
BOOOOM!
Glancing at the mirror to see the pothole I must have hit, I see smooth
pavement-and a dark-colored object roughly the size of a good cigar
flipping down the road! Heavy traffic prevents the brake stand so I can't
go back to look. It is then that I realize that all I hear is a smooth
running 5, no CLICKS!
Once home, cursory inspection reveals- nothing!
No leaks, no obvious missing pieces. Car idles, boosts, steers, and stops
normally. 
What the HECK just happened?
It's done this noise for many weeks.
TIA,
Rob
proprietor of
uneasily silent 5000CS Turbo...