Kawasaki Prairie 300 gears slipping/poss spider gear Need Help!!!

[JWD1977]

Hit the gas just hear gears the drive system moving/ dont go every now and then will catch and move?

I purchased this Prairie in 2000 new bairly drove it but, some how the factory didn't put a good seal on the rearend and it started making a squeeling noise thought it was a rock stuck in the break pad so didnt think no more of it but eventually it got to were when you put it in gear and give it gas nothing happens just the sound of the drive system moving and like teeth not catching... Thinking possible spider gear but, not sure I have tore down the rearend and the gears at the rearend seem fine. havent ventured to far into it being that the tear down is no simple task would like to have a better idea of parts I may need before getting it broke down.. Dont want to leave it in parts while Im waiting for parts... Anyways its a Kawasaki 300 prairie 2000 model - Automatic Anyone with more knowledge would greatly be appriciated.. Thanks