Kevin Lawson

Ok guys I have a 2000 chevy blazer ls 3 button 4wd system...I push the button for 4hi or 4 lo light comes on sounds like everythin is engaging the cable that comes from under the battery pulls for,the front end ...but there is nothing going to the front tires I have crawled under it and in 2 wheel the axle that's goes to the front turns by hand then when I put it in 4hi or 4lo and,put it in park I cant turn the front axle by hand...and it does turn while vehicle is moving. In 4hi or 4lo but still nothing...I'm at a loss don't know what else to do