I assume you are having issues with them not locking up in the auto position? If that is the case be sure to check the whole system out, it might not be the hub at all. There is an inner "bladder/hub" not sure what it's called but if it is leaking your hubs won't lock either. I have chased this problem from top to bottom my whole system is pretty much new vacuum line, hubs etc etc and I still have an intermittent problem with the hubs engaging in the auto position, I think the system is just sensitive if you have a tiny bit of water due to condensation from hot and cold cycles it will freeze up and not work. I have started just locking my hubs in before leaving the driveway if I think I am going to need 4x4, it's the only sure way you will have it. In hind sight I wouldn't have replaced my hubs at all.
2008 F250 ext cab, 4x4.
