After removing the snow thrower attachment from my new to me model 1641 Cub Cadet, I noticed a small patch of transmission oil that leaked from the base of the filter. A quick check hinted at bad news. The guy I bought it from had just changed the fluid, installing the correct filter but heavy brown smelly old school tractor oil, he probably had on his farm. I have since drained and refilled with hy-tran plus a new filter. I don't think the machine was operated very much with the wrong oil in the trans. I wonder what kind of damage has been done? I suspect I will have to flush it at least once more to clear the lines etc.