lockout hubs

[cjrichtig]

Probably a dumb question, and im sure ill get some of these..., but why do the 1999 powerstrokes have lockout hubs, and automatic 4 wheel drive selector on the dash? i thought the older 4x4's had manual lockout hubs, but the newer now are automatic. how can a truck have both?

[HVAC SuperTech]

if you leave the hubs in the auto mode, then they will lock in when you turn the dash selector to 4x4. Assuming the vacume system in the truck is working ok, and the lines running to the hubs are good. The hubs work off of a vacume system in our trucks,

Now, if you turn them to lock, then no matter if the vacume system is working correctly or not, when you turn the knob to 4x4, they are already locked in and ready to go. locked basically means youre running around with hubs locked at all time.

[Southpaw]

They have automatic hubs and a manual override.
You can shift in and out of 4 wheel drive via the switch in the truck. If your hubs stop working that way, you can manually lock them in at the wheels but you're not in 4 wheel drive until you flip the switch in the dash.

[Zaairman]

They're there to cover your ***.