1997 Ford Ranger makes loud noise from right front hub

1997 Ford Ranger mileage: 61,000. I have automatic four wheel drive. Recently, the right front hub started to make a loud grinding noise whenever I disengage the four-wheel drive. The autohub is not fully disengaging the four wheel drive and, or so I think. It engages roughly, and disengages smoothly on the fly, but once I stop and restart at say a stop light, there is an awful grinding, "whizzing" noise. Is this just the hubs that need replacement, or something more serious? I have been told auto-lockers are no good no matter who you get them from, be it Ford, Chevy, GM. Instead of replacing the autos, can I just put in manuals, if this is even my problem? The truck performs just fine once I get into 2WD.