2001 Arctic Cat 500 Automatic

Hi everyone. I finally decided to join the group. I’m glad I did. I’m hoping to fix a problem with my atv. So I have a 2001 Arctic Cat 500 automatic. When a buddy of my mine was riding it yesterday, I noticed when he was stuck trying to climb an ice hill that only one tire was turning. He was in four wheel drive. I would think that both wheels should be turning. Does this mean I need to replace a cv shaft? Also, is there a way I can verify this by checking the front of the wheeler out? Thanks for any help or advise! Jason C