it sounds like a front pump gear whine . if the oil levels are good and your not finding any metal in the samples then keep on driving unless you want to take it apart and try swapping in a new or different front pump
...PM me for advice or service questions.
1988 S4 Elfenbein Perlglanz with a full Pearl Gray leather interior, Auto, Motorsport of Utah X pipe
1985 Euro Auto, Blue /Blue
Past survivors sent to new happy owners.
1986.5 Auto, Meteor metallic/Tan 2.0
1982 Wessach #13 auto.
1985 Euro 5 speed with big brakes Black/Black 16Valve
1986 5 speed Mossgruen,Brown
1986.5 Auto Meteor metallic/Tan 1.0
1984 Euro Auto, Grand Prix white/ Tan