I dont know what its doing but for the last 2 months when ever i am driving along and i go up a long hill, I hear a rattle or little noise under my druck. My guess is that its the trans but i could be wrong. I have the Off Road pkg so i look at all the skid plats there on good. I dont know any body got any thing.

 

Don't know if you F-150 has these or not. My F-250 was doing the same thing. I found the small metal heat shields on the exhaust Y pipe had cracked welds. These are really hard to see. I found 3 cracked. When I took it to the exhaust place to have then re-welded they could not find them until I pointed them out. The heat shield on my truck near the oil filter could be pulled 1 inch away from the exhaust pipe. Grab a good flash light and look at these welds really close. You may want to take a small screwdriver and gently pry next to each one to see if it's cracked. Hope this helps.

GA-V-10

 

Do you feel the noise through the floor or gas pedal? If so, you probably have the trans torque convertor problem. SOme say it is fixed by a simple fluid change, however, there is a dealer service bulletin on this which calls for a reprogram by the dealer. This fixed mine. Some say it feels like driving on "rumble strips". Mine felt kind of surging and growling like.