I dropped a 10 mm wrench while replacing the battery. It sounded like it fell through to the undercarriage but I couldn't see it from above. I drove it around the neighborhood and didn't hear any strange sounds. Do I need to be concerned?
My car has 50000 miles.
My car has an automatic transmission.
You may not have any worries unless the wrench gets in a place where it makes noise or interferes with vehicle components. The wrench may have fell into the inner fender. You may be able to locate it there. Have a local technician help you retrieve the wrench or if you begin to notice any noises or drivability changes.