I think I wore my eliptical crosstrainer out. It makes a clackity sound. A very loud clackity sound in the big wheel area. and pieces of ground metal have come out onto the floor on the left side. Can you help me figure out what is wrong with it? I have called Sears. but they what a small fortune to fix it. I have a friend who will fix it if I can get the right part & tell him what is wrong. Please help...