Since this dryer was probably 15+ years old took it apart and gave it a good cleaning, which was long overdue. Replaced the Thermal Fuse and Hi-Limit Thermostat and the the exhaust duct which had a lot of "caked" lint. Replaced the drum belt (which was ready to go ... cracked in two places) drum support rollers and drum guides. The dryer came on normally and heats fine and the squealing has stopped. Will plan on routine maintenance in the future since the lint really does build up quickly and clearly affects the dryer performance. Until could actually see the buildup, especially in the exhaust duct did not seem very blocked, but it was.