I just bought a 1987 chevy blazer 4x4. The seller put it in 4x4 and he grinded a few before he was able to set the shifter into 4x4. He drove a little foward and it sounded like it was in 4x4 by the low power it had and high revs @ such a slow crawl. I said fine it works and bought it. I took it to the beach. Its automatic, I put it in neutral and held the brake, grinded a little until I was in 4 low. I went foward, into the sand and found only my rear wheels had locked into compound low. My front was dead like a 4X2. What could it be? Thanks, Chris H