In my '04 safari, I'm starting to get a little slip taking off from a stop. It happens maybe once every 100 miles but when it does it, you can give it gas and the van won't move for a second or two until it kicks back in. I also sometimes get a little shutter on the interstate and this happens almost every time I drive on the interstate, which is not very often. It almost feels like I went over a bump, but I know otherwise. I've recently changed the transmission fluid and filter but the last two changes since I bought the van, I've used supertech dex/merc. I'm wondering if changing to a high-mileage transmission fluid like valvoline would help. Maybe supertech even makes a high mileage fluid? Last time I changed the fluid, I only got about 8k miles out of it before it started turning color. Sorry for all the vagueness.