I have a LT 542-H riding mower with a hydro static transmission. I stopped to gas up and when I got ready to start mowing again it will not move. I have tried to disengage the transmission lever on the rear of the mower to put the mower around but the wheels still will not turn. The pulley and fan on top of the transmission turn, but it makes a funny sound and still won't move. Any suggestions? I see no leaks around the hydrostatic and I find no place in the manual where it shows how to add oil to the hydrostatic .

Thanks