2012 Sportsman 800 rear differential issue

Hey everyone,
I think I have an issue with my rear differential, transfer case or the locking solenoid. I am hoping for some help on diagnosing my issue before I go and tear about the bike.

After a weekend of very ruff ridding I noticed my quad needs much more power to move. After the weekend I went to move the quad out of the garage and I snapped the rear right axle after making a tight turn. I replaced the bad axle and drove it down the street and snapped the other rear axle. In neutral the quad rolls very nicely with little resistance. I jacked the quad up, put it in 2×4 and turned the tires by hand and it does seem pretty restricted (hard to turn). I then took both axles out and started the quad to spin the internals and it again seems more restricted than it should and is pretty loud. Can any one help me determine if it is the transfer case, rear differential or the locking solenoid. It almost seems like the limit slip is not engaging and the rear is locked all the time. Thanks in advance!