I was stuck in sand on the beach. When I locked the hubs and put it in 4-wheel-drive, one rear tire kept spinning and the others didn't move. Shouldn't both rear tires have turned when the hub was locked? Is there something wrong with the locking differential? I don't want to take the car to the garage if this is normal.

Dosen't sound like the 4 wheel drive is working at all! mabey u should have it looked at.