Sounds like you lost a axle seal. You can pick up a new one at Low Range or Hawk Suzuki, or pretty much any of the sponsor web sights. I just really like the two above. You will have to pull the rear axle, swap the seal out, the put it back in.
If you have a Tracker you can pull the axle without removing the backing plate. If you have a Sammy you need to disconnect the brakes and pull the backing plate as well. Unless someone did the SJ-410 backing plate conversion.