I have a 445 and have ran it all spring& summer, I purchased a new 52" plow with tilt and all and put it on tonight. The tractor has always had a whine to it I thought was odd but normal. Well come to find out it was not normal and was telling me a valve was stuck. Up and down works great, but tilt cylinder wants or pull to one side (depending on how you have the hoses). The bottom right (inside) valve is not pressuring from my diagnosis. What's a good place to start for troubleshooting. Bottom leaver is solid but still pushing fluid out of bottom left (outer) side of valve body. Need to figure something out before snow flies. I took lower end cap off the valve body (has ball bearings springs and two bolts) the shank wont budge but the spring turns with pressure. That's as far as I've gotten. Thanks guys. I can get pictures or a video if your confused.