my brother has a 04 scrambler 500 and the chain kept loosing up upon further inspection we noticed that you could pull up on the chain and the right side of the axle would move front to back inside the housing is ti a bad bearing or is something just loose also how much work is involved changing it out ive done a few 300ex axle bearings and it wasnt to much trouble thanx for any help it may still be under warranty but just looking for info befor he has to bring it to the stealership thanx again.

 

Sounds like bad bearings to me. Make sure the swing arm b ushings aren't shot as well. Should not be too tough, but get a hold a manual for back up.