I have a question. I have a 93 F150 and when the hubs are locked but not in 4 wheel drive the truck is smooth. but the hubs are unlocked the truck shakes real bad at 30 mph. The F150 has a total of 6" lift (body & suspention).
Thanks in advance.

 

Lift the front of the truck, turn and shake the wheels, see if anything is loose or binding, that would be the best thing, the only thing would be is the hubs arent completely unlocking.