If your dryer just started making a loud banging noise it is probably one of three problems. Typically if one of these three things are the issue your dryer will still be turning on and heating up.
Most of the issues that cause a loud banging noise inside your dryer will be fairly obvious once you take the dryer apart. Some parts will look worn out or broken.
Damaged drive belt
The drive belt is a long skinny belt that makes the dryer drum spin. The belt wraps around the dryer drum, a tension pulley, and the drive motor. After a while, the belt can fray and become damaged. A damaged or frayed belt will become noisy. You should inspect the belt and if it has any visible wear, replace it.
Worn out Drum Roller
Another typical problem is a drum roller wearing out. Most dryers have two drum rollers in the rear supporting the drum. Some newer dryers have two more support rollers in the front. When worn out these drum rollers cause the dryer to make loud rumbling sounds.
It’s pretty easy to tell if these rollers have worn out once you begin inspecting them. They look like roller skate wheels. Inspect all of the drum rollers and if any look wore out, replace them. The wheels are fixed on roller shafts which can often be reused. Clean the shaft before putting the new roller on.
Worn out Drum Roller Axle
The third option is a worn-out drum roller axle. Most dryers have two drum rollers in the rear supporting the drum. Some newer dryers have two more support rollers in the front. When these wear out they will cause the dryer to make a lot of noise.
The first step to finding out if a drum roller axle is worn out would be to remove the belt from the dryer drum and attempt to turn the drum by hand. It should rotate easily. I also recommend removing the drum and turning each of the Drum Roller wheels by hand. If the wheel wobbles around a lot, the wheel or the axle has gone bad. Slip the wheel off and see if the axle has been worn down.