2003 F250 Front End Vibration/Hub Questions

[jlcljayne]

I have a 2003 F250 Superduty 6.0 Diesel that I just bought. It has a front end vibration that gets worse at highway speeds but isn't totally rotational inline with the wheels. It increases with speed though.

It has the auto/lock hubs on it that turn freely between the settings but the front driveshaft is spinning as if it were locked. I turned the hubs back and forth...tapped them with a rubber mallet and drove backwards seeing if they would unlock but driveshaft still spinning while driving. If the auto hubs were working right, I should be able to spin the front driveshaft freely either until the tcase is locked or the hubs are locked...correct?

The front slip joint in the driveshaft is tight but maybe the ujoints are dry. I would really like to get this into 2wd mode to see if the vibration changes or do these trucks always have a rotating front driveshaft in 2wd mode?

Any help or thoughts would be greatly appreciated!