I have a 99 f350 single rear wheel 4wd, after having a shop replace the ball joints I noticed when the truck hits rough pavement of any kind the front end starts roaring and vibrating at all speeds. After I took the truck back I was told it was the wheel bearings not anything the shop did although I never had this problem before they worked on it. I replaced both unit bearings myself and reinstalled the factory lockouts after about 800 miles it is doing it again the only thing that stops the roaring is to reach up and turn the switch to 4hi for a second and the noise stops instantly until I hit another bump. Could any body tell me how to fix this problem or what year Dana 60 would swap in without a lot of modification..

 

You need a new axle assembly for whatever side is acting up and you are supposed to replace the steering knuckle with all the seals as well. The guys that reinstalled your axle stubs could have screwed them up. Because what is happening is the axle is spinning inside the spindle with all its seals when you don’t want it do because it is binding up whenever you hit a pump or rough pavement like you said and spinning with the wheel but doing it very rough. You could replace it with an entire assembly from a later year ford with not much problems, just get something with the same gears.