We need more info from you before we can provide possible answers. First, model and serial numbers from the unit so we know what you have. Second, please paint us a better picture of what is going on and what you have done to rectify the problem. When was the last time the drive belts, tensioner arms and pulleys were serviced? Remember we are not standing next to you, with a strong drink you provided to see what is going on. Also see you have two threads with the same problem, check those things Bert asked about in the other thread, then stick to one thread to eliminate confusion.