New to forum.
i have a 1995 f-150, five speed manual, auto hubs, 209,000k, stuck in 4x4. It feels as though something is binding. I have sprayed penetrating lube around linkages and shaft that enters into case from linkages. I lubed these areas on preventative measure even before I had this problem. Fluid was changed about this time last year and only driven several thousand miles. Never acted up until now. Truck has been well maintained and never had any major work done to it. I regularly engage and operate 4x4. Any ideas?

Thank you in advance
myles