there is a hissing/air release noise when the car is in drive. brake: no noise on 2009 Volkswagen Passat

There is a hissing/air release sound when my car is in drive and when I brake the noise stops.

by in Stockton, CA on September 11, 2013
1 answer 1 comment
ANSWER by on September 11, 2013
Have the brake booster checked out. Before it gets worse!!
COMMENT by on September 11, 2013
thank you very much. Is this normal or maybe a defect? thanks