Small Engines (Lawn Mowers, etc.): hydrostatic drive, hydro pumps, hydrostatic drive

Question
I have a '93 Grasshopper mower model #720K w/ 20hp Kohler. The mower has been sitting for over a year. After getting it running again the mower will dot drive at all. It's running fine and the pto drive works fine but no drive either direction or either side, does not even try to move. When I try to drive there is a slight "buzzing" sound from the transmissions. Fluid level in the hydro tank is full. I just am having a hard time imangining that both transmissions went bad at the same time.

Answer
Someone released the pumps to move the "Hopper" when it was dead.

Look for the hydro pumps, they will be the things that have the belt attached. On the pumps there will be a Bolt looking thing with a hole drilled through it.  Tighten this "valve" down and the "Hopper" will drive.