i have a '07 ford xlt 4x4. there is a grinding noise from the front end like if it trying to engage the fourwheel drive while still in two wheel drive. this is occuring while i am driving but the grinding goes away when i shift the truck in 4 wheel drive then back to 2 wheel drive. if anybody has had this problem before, found the problem and solved it please let me know what i can do. thks.

 

Sounds like you have a vaccum leak in your IWE or somewhere in the 4 wheel drive vaccum system. The hubs are actually trying to engage thats what makes that noise. Get under the truck on the hub you will see a vaccumn line going to each wheel take one off at a time check for vaccumn you should have about 20 pounds at each one.