My kenmore stack dryer has been squeaking lately, but drying fine. Today it sounded as if it was tumbling bricks. When I opened the door, it went, 'clunk'. And would do nothing after that. Any opinions? I've had it 17 years, has been doing fine... except for the squeaking, until today.

With 17 years it's probably time for a replacement. That said, a sound like you noted could be a support bearing or rollers.

Tear the dryer down, clean and lubricate it with white lithium grease.