Dumb question about 4 wheel drive on my 72 C20

[Altec]

Good info here. Maybe I can help get it all into one post.

Unlocked Hubs/2-Wheel Drive:
-Only the hubs spin. Drive shaft, and axle shafts do not turn. Least wear, and least drag on the system.

Unlocked Hubs/4-Wheel Drive:
-Drive shaft, and axle shafts spin. No power transfered to the wheels. Results in unnecessary wear on transfer case, ring and pinion, and axle shaft seals. also results in increased drag on your drivetrain. Lowering efficiency, and slightly higher percentage of power lose.

Locked Hubs/2-Wheel Drive:
-Same results as unlocked/4WD. More, or less. At full lock, or close to it some popping, and jerking can be felt in some cases. Result of the joints on the axle shafts binding.

Locked Hubs/4-Wheel Drive:
-Transfer case, drive shaft, axle shafts, and hubs all spinning. Increased wear, and lower efficiency caused by drag in the system.
-Dry surface use in Locked/4WD results in problems. Even with a open differential. The front tires are allowed to spin at different speeds, but since the front axle is now tied to the rear axle binding simply can not be avoided. Because the back of the vehicle will always take a different path then the front. The resulting effect is the "bucking" and other problems felt when trying this. The only way around this is with a transfer case with a built in differential. Options for this are slim. The popular choices are the NP203, and the NV245/247, and maybe a couple more.