I was riding with my mother the other day in her 02 Caravan (has 208K miles) and noticed that as she would turn or go up an incline, I could hear a water swishing sound like you hear from a clothes washer. I spoke to a friend today whom has a 05 Caravan (with 104K miles) whom was complaining about her van making the exact same sounds. Does anybody know what is making this noise and how to fix it?