My Maytag dryer model MDE3500AYW is making a loud squeaking noise. What could be causing this and how do I repair it?

There are several drum support rollers and a belt tensioner that can squeal when they get dry of white lithium grease. Here is a manual: https://dl.dropboxusercontent.com/u/8010163/Maytag_Square_front_Dryer.pdf
You will need to tear it down and wash out all air ducts with soap and water by removing them and cleaning them out. You will have to take each roller apart by removing the pin and then greasing them with white lithium grease. If the pins are scored you will have to replace them, but the rollers are very cheap. You will still need to grease them with lithium grease (hi-temp).