Help! I have a 2001 Expedition. Makes a rumbling or growling noise during acceleration. Stops if I take foot off accelerator. Also stops if brake is pressed and doesn't do it in reverse either. Can be driving and then shift into neutral and it will stop! Please were desperate for ideas! Thanks in advance!!!

 

Can't say for sure this is what you're hearing, but I just started researching a sound with my F-150 and came across TSB 05-23-3. This is a technical service bulletin regarding the issue of "some vehicles may exhibit an axle whine or hum during acceleration, deceleration, and / or cruise."

Not sure if this is the same sound, but your Expedition is covered in the list of affected vehicles.
You can read about it at:
http://www.ford-trucks.com/tsb/fullt...hp?tsb=05-23-3

Hope this helps.