I purchased a used 2005 HAH end of August 2006 with 8000 miles. On way home from dealer had the droning noise! But got that fixed last week. I have a thumping(like bass noise) coming from the back end at low speeds when on anything but smooth roads. Even pulling into the garage which has about a 2 inch separation from driveway it thumps. Took it to dealership yesterday... Of course was told this noise is not anything out of ordinary as the battery in trunk weighs 200 lbs. I drive 7 miles of bumpy roads and 8 of smooth and this noise is driving me CRAZY. Does anyone on this wonderful site have any suggestions or fixes?