I bought this mower used, and it worked fine when I test drove it. After 30 min of mowing the mower gets sluggish, and the left tire will stop moving. I figured it was the hydrostatic transmission, but this model's transmission is "unserviceable". Before I buy a new one, I wanted to know if I can drill and hole in the top and bottom. Drain the old oil out and add new oil. Just wanted to know if anyone has tried anything like this? or if anyone has an idea before I scrap the mower?