You are going to have to give us more info on what is happening, before we can help you. Remember we are not standing next to you, with a glass of wine in our hands, to see what you are doing and what is happening. Few questions we need answered. Do you have a manual or electric PTO? If electric, do you hear anything when you pull the switch? When you say does not engage, do you mean nothing happens or they try to engage but just stop? With the unit shut down can you turn the blades by hand? When you did your maintenance, is it possible you assembled something wrong. Remember we can’t see your unit, you are our eyes, paint us a better picture.