Sedona has 120,000 miles and never any problems. I've taken good care of it, except I never changed the timing belt at 60,000. Recently, I notice a soft thudding sound coming from the front of the engine. It sounded as if it were coming from the timing belt area, and I thought that the belt might be fraying inside since the belt had never been changed. I opened it up this weekend and checked it. No frays, and all the timing marks were correctly lined up. The belt was actually in decent shape for 120,000!! I changed out the belt and water pump and closed it all back up. Started the engine, and there it is again, still intermittent, but definitely there. It's definitely not metal, but I can't figure out what it is. Any thoughts?