I have a chevy pick-up truck the year 1995 Z71. I put the truck in 4x4 high for the first time this year and did not get a light near the gear lever nor did it go into 4 wheel drive. I check the transfer case with it in neutral and the front shaft would turn freely, then put it in 4 wheel high and it would not turn. I also drove the truck on dry pavement with the 4 wheel drive high gear and 4 wheel drive low gear and had no bucking of the front end when I made turns in a parking lot. Any ideas