My Papaw has a f-150 and about a week ago it started making a rubbing sound since then it has gotten worse and we cant seem to find the problem. It makes this sound when you are accelerating below 1000 rpm's and makes the sound when you hit 2000 rpm's. It sounds like it is either coming from the bottom or the front of the engine. I took an audio recording so you can get a better feel for the sound. Thanks in advance.
Truck Noise.html

 

Haven't been able to hear the recording, however, does it do this whether the vehicle is moving or not? If only when moving , good idea to check the driveshaft u-joints. If looseness is not apparent , look for rust trails at the joints themselves. If the joints were replaced with aftermarket joints they will most likely have grease fittings so they can be lubricated. If original there usually will not be fittings available. Sometimes they look OK , but still can produce noise or vibration and the only way to confirm is to actually remove and physically check.

 

Nevermind we have found the problem it was a metal clamp that was broke and was rattling the right way to make a sound at a certain rpm.