1994 Ranger front end noise.

Sometimes when driving my 1994 Ford Ranger in two wheel drive I get a strange whirring/grinding noise from the front end area. The truck is a 4x4 with the auto locking hubs at the front. I suspect it is them that is making the noise. The nosie goes away by itself someitmes or when I stop and go again it goes sometimes also. If it is the hubs and what are they doing? It almost seems like they are trying to engage into 4 wheel drive. The steering seems a little sluggish now and someitmes it feels like it is pulling to he right. Could it be one hub trying to engage? What do I do if that is the case?