Resistance in 1st gear, 1989 Toyota Pickup
 

I drive a manual 1989 Toyota Pickup, 4 x 4. Recently it has been giving some very strong resistance when I drive in first gear from a dead stop, to the point where I can't go forward unless I shift into 2nd. This resistance is not present if I start in 2nd gear. Also, there is resistance when I am coasting in neutral at a very slow speed (<5 mph), as if the emergency brake was on. Any ideas of what this may be? Clutch, transmission, spider gears?