I have an old Yale manual transmission forklift that has sat for a couple of months. It ran fine the last time I used it, but when I tried to put it into gear today there is just a grinding noise. It only has forward, neutral, and reverse in the floor. I removed the cover plate on the floor and the clutch pedal is engaging what I believe is the pressure plate from the engine. When the engine in off I can easily move it into either forward or reverse. Is the pressure plate stuck? Not sure what is going on. I have only had the lift for a about 4 months. Thanks for your help!