My father-in law has an 04 f-150. Last night he mentioned to me that he hears a slip or spinning noise mostly when taking off and stopping. It gets quieter as he picks up speed, like it is catching up. If he puts it in 4-wheel high then the noise never happens. I wasn't real sure what to tell him as I haven't dealt with 4X4's very much. I though I might get lucky and it would be a common problem with these trucks. Any ideas?????

 

Several write ups about the 4WD solenoid valve. Camplaints are of a different sound than spinning but who knows.