I have Simplicty Soveriegn 7100. I have what appears to be a power issue. When mower deck is engaged and going up hill the tractor boggs down to the point that it engine coughs ans almost stalls. Mower is free and not bound. Any ideas? Also does anyone have the instructions on how to fill the Hydro/Tranny with fluid? I am told it is a big production? I am new to Simplicty.