Sorry for the basic (maybe even stupid) question in advance. I am new to diesel trucks / 4x4s and I am trying to learn....

I have a 2005 F350 4x4 (DRW) truck. The front hubs have a "Lock" position and an "auto" setting. I have read the manual but not sure if I understand it correctly...? I currently have the front hubs set to "auto" and when I turn on the "4x4" **** in the cab, the front wheels engage.

My question is, when would I set the hubs manually to the "Lock" position?

-Thanks

 

the hubs are controlled by a switch on dash and a vaccum pump if you get a vacum leak the hubs maynot lock in so they gave the option to get out and manualy lock them im

 

The Electronic Shift on the Fly (ESOF) system uses vacuum pulses to lock and unlock the hubs. It's not always the most reliable. The manual hub lock is for when it decides not to work and you really need 4WD.

 

Ok, thanks guys, makes sense! I'll try not to kill everyone with silly questions. But I grew up never doing anything to my own cars / trucks and over the last year I have started to do minor stuff myself, so far I have learned how to change my own oil, change shocks, installed a trailer hitch etc.... I know it's really minor stuff but for someone new to the auto mech world its a first step... I am trying to be more self-sufficient! Thanks for the help!