What is causing the SUPER loud noise from my dryer
It's difficult to say without actually standing in front of it and observing the noise, but I'm going to guess you have some shot bearings somewhere. It's easier to point to them in an image to suggest where they may be descriptively:



To the left you have casters to keep the dryer on course. Applying some Teflon (or silicone) may cure it. To the right, the motor - and the sound you're hearing may mean that it is dying. That's not something you can really service beyond replacing it.

It could also simply be the belt that's attached to the motor. The same 'belt dressing' that you can buy in an auto parts store to cure a fan noise in your car will likely show (or eliminate) the belt as the culprit. It is probably quite old if it hasn't been replaced since being purchased. The inside of a dryer can get quite humid, so those belts can last for a really long time.

So check lube or 'dress' anything that helps the dryer spin, except the motor, first. If that fails, then look into getting a replacement motor (or new dryer, possibly). Rule out anything that has steel bearings first, and the belt.