I have a ford 640 tractor, sometimes it does not want to go into gear. With the clutch pedal depressed it still wants to grind. If I idle the tractor down to 450 RPM you can usually shift into gear and you are good to go. Also sometimes when you push the clutch pedal in the tractor does not want to stop unless you tap the left brake pedal. By tap I mean almost just put your foot on the pedal and the tractor stops. I actually split the tractor today to see what is wrong. I can not see anything obviously wrong. I was thinking it was the throw out bearing before I split the tractor but it seems to be in good shape and travels freely on the shaft. Could it be a problem with the pressure plate. The clutch pedal adjustment eye bolt on the side of the tractor was screwed all the way in so I had no adjustment left.