"Cleaning" the hub seals will go nowhere..too cold..and also, the solenoid valve
http://www.geocities.com/lmp4203/kiasport/DSCN2448s.JPG
itself gets frozen either closed, open, or somewhere in between....no good.
Best before changing them is to invert the position of the spring in the vacuum hubs. DOne easily: take them off (6 bolts), remove ring clip and tke pieces off keeping them in proper order, and when you have the piston off, put the spring back in then piston and all the rest.
THis is exactly like putting "manuals" ON: the shafts will keep rotating with the drag tha t goes with it, but they will work and as soon as you shift the TCase in 4wd, you'll have it.
THe automechanical are available from WARN as part number
61918. THis is a KIT and involves the spindle nut, locking key, cam assembly and hub. INstallation manual here:
www.geocities.com/lmp4203/hubinstall.pdf
Someone on this forum got them for about $120 pair lately. I'll look for the thread...
come back if need more info