Hello I have an old MF 36 hay rake that I'm doing some general maintenance on. I don't have an owners manual for it and haven't been able to find one for download. I was checking the gearbox and pulled the plug to find it coated in grease. Confused I pulled the cover off to find the entire gearbox filled with grease. I'm not sure if that is normal for this cause I am used to putting gear oil in these not grease. Hopefully one of you have used this type of hay rake before and can chime in weather I should clean it and repack with grease or clean and refill with gear oil. Thank you. Corey.