[s-cars] mystery noise

[Bill Healy]

I'm hoping someone out there has had a similar noise...

Its an intermitent rattle-type noise which seems to be coming from under the
car, presumebly from the front pass side. The noise sounds like a light
metal "clinking" sound. It occurs when the car is rolling, it occurs when
the car rolling, running or coasting. It is not effected by braking or road
irregularities. I thought it was related to the front brake backing plate. I
jacked the car up and manually rolled the wheels, no obstruction, no wheel
bearing noise, CV joints are good.
It can be aggrevated by sharp right or left turn but only occurs when the
car is going straight.
Differential bearing?

Thanks for any suggestions,

Bill Healy
'93 S4
206K