I was changing the motor oil in my Grasshopper and in an unexplainable brain cramp began pouring the 10W-30 motor oil into the hydro system. It's only 10 hours (engine break-in change) and the hydro was completely full. I only realized what I was doing after the oil started running out of the top. I have NO idea how much of the quart of 10W-30 made it into the hydro case and how much spilled over. There's still some left in the quart, so it's somewhere between a 1/4 and 1/2 of a quart that made it into the rerservoir. It's obviously over-filled now. Do I need to completely drain the hydro and re-fill? It's a 5 quart reservoir. Thanks for any help.