126 Chassis metal Sunroof ıs supposed to move up and down and forward and backward. Mine got stuck ın the UP posıtion and only one sıde would go up and down. The other side was stuck. I pulled up on the open side and pulled out a broken almunimum part and wiggled something around and then it shut. But it did not do so properly and it still won't open (front to back) Does anyone know how to open and diagnose and repair this mechanism. Thanks. (This is a 1987 300 SDL Turbo Diesel--I don't think the engine type matters)