OK, so the noise isn't coming from the unit being actually out of balance. Is it a thumping noise, like a flat tire?
If you start a cycle and then open the door, does the noise stop right away or does it continue for a little bit?
Here is a link to a video showing how to access the interior of a Maytag dryer. The parts you most likely need are the drum rollers.
You can order the parts for your model at the following link.