I recently had the timing belt, balance shaft belt and oil seals replaced on my '98 Odyssey. Now the van has a persistent new vibration at all speeds. It seems to run fine, but we don't like that new hum. We checked and replaced the front motor mount which was worn out, but that made no difference. I've read that you can get major vibration from the balance shaft belt sprockets not being properly aligned, but no one mentioned if it could be a little off and create a noticable but not bone shaking vibration. My mechanic, not having driven the van before, doesn't notice the vibration as something new, and it's a fair amount of work to go in and check, but I don't know what else it could be. Any thoughts?