I have a 1999 Villager with 90,000 miles. Runs great, but wondering how often to change trans. fluid? The manual just says "inspect" at certain intervals, but never "replace." I purchased the van at 60K miles and I've never had any trans. problems. Since the fluid looks and smells fine, too, it may have been changed at least once since new I am assuming. I am asking because I want to pull a pop-up camper some this summer and want to avoid any problems. Some say it may make things worse if you change it too much, so I wasn't sure what to do.