If you own one of these riding mowers in my opinion its gotta be the worst to work on this decade,I HAVE HAD THE OPPORTUNITY TO WORK ON TWO OF THEM WITH SIMILIAR PROBLEMS.It is sold as an automatic,but is not a true hydrostactic rearend.Deck has to be removed as well as the steering column has to come loose just to put drive belts on.If you would care to see it and a breakdown of the rear end with pictures,check my site at http://news.smallenginetrblshtng.com
Ihope you dont own one, if you do better keep the owners manual handy.