When four-wheel drive is engaged, the front tires grind and then lock up?

You either have a CV axle that is bad, or the front differential needs to be rebuilt, let's start by removing the front CV axles for inspection, here is how the job is done. With the axles removed try spinning the wheels to see if they rotate smoothly. Check out the images (below). Please upload pictures or videos in your response to the problem so we can see what's going on.

thank you for your input. i will do as asked in the near future. i live out in a village that has about 700 people in Alaska and the only way to come here for a few hundred miles is by plane or barge/boat. So we don't have a shop to bring trucks to and have to be willing to do the work our selves if we want to keep our machines running. When i get to this step i will make a video and send it to you.

Alaska must be quiet at night :) no problem on the delay let me know how it goes.

anything?