I agree with Steve, tear it down, rebuild/repack. It could be low on grease and the increased friction could be causing the heat.
Good luck!
My son's 1989 Bronco front left hub (part that sticks out with the hub
> locking machanism) gets hot after a short while of driving. Too hot to keep
> my hand on.
> First suspected sticking brake caliper. Caliper is much cooler than hub.
> Jacked up front end and spun wheels - they are both free so I don't think it
> is sticking brakes.
>
> Last time hub was in 4x4 mode was back in February when I got stuck in a > snowbank.
>
> No characteristic noise, smell, pull or shimmy - just the hub is hot >
> He bought it used two years ago, can't tell you exactly how long it's been
> getting hot but guess about a month or so.
>
> Any thoughts???
>
>