I have a series 2000 cub, was bought around 1990, has been a great mower and used to plow snow. it will start, deck will turn on, but won't move forwords or back, when i jack it up the tire turn oposite of each other, like it's stuck in gear i took speed lever rod off and moved it to the nutral position by hand, and get the same thing. any ideas on were to start to look for the problem or what it might be? i don't want to take rear end apart untill i have too