My lesco 48'' walkbehind has roughly 1800+ hours on it (hour meter no longer works)I bought it used, this summer for super cheap. The machine operates flawlessly EXCEPT when going parallel across a hill with the left side of the machine facing down the hill. I can go about 30 feet and then the hydro goes completely dead, i lose all hydrolic power on the left side of machine, the right drive wheel is fine. And if i go acorss the hill or any incline parallel with the right side of the machine facing down hill it works just fine, has no issues whatsoever. Anyhelp would be nice, thanks. I've thought maybe air in the lines, but I don't know about that. Could it be the filter? It's a earlier model late 2000-2001.