Just bought my first 6.0 after many years of owning a 7.3. When I got the truck home I noticed that my hubs where on lock not auto (guess they did that so I wouldn't see that the ESOF wasnt working) I Started looking things over started with checking to see if the hubs where leaking I put my vacuum pump in the line at the hub pumped it up to 25 and it held there on both hubs Next I pulled the hublock vacuum solenoid from my 2002 and put it in there still the hubs wont lock Then I checked the solenoid for vacuum put my vac gauge on the line that goes to the diff turned the selector switch to 4X4 vacuum climbed to 15 held there for a little bit then dropped Turned it to 2X4 held at a lower reading then dropped. Then I pulled the lines from the solenoid to the diffs checked them all for leaks that was all good
questons are
Is the solenoid is working how it should
What do I check in the hubs or is the hubs no good

 

Pull the hubs.. clean and grease...

 

Solenoid is working properly

 

I have been waiting for over a month for new knuckles for my f350... Dealer states they are to pitted to rebuild...the tech took pictures and showed me the hubs were full of water and mud... The knuckles are 2000.00 a piece... With that said I would pull the hubs and clean and grease them.... Mine are under warranty.... If it were out of pocket I would be kicking myself...

 

I pulled the hubs and everything was clean nothing other than grease in there The truck is a 2006 so I cant pull the hubs apart and clean them like the older ones. basicly if they are no good I will have to pickup a set from the stealership because there is no other altrenative ($398 CDN a side) I think I might have not done my vacum test wrong the first time because now I cant get the vacum to hold Guess I will have to pickup the O rings ($43 a side) and start from there