The dryer drum turns because a belt loops around the drum and the motor pulley. An idler pulley keeps the belt tight. Many models also carry the drum on rollers or glides at the front and back. When one of these parts wears, the drum usually tells you before it stops. Your job is to hear it early and write it down.
What you are listening for
A thin squeal while the drum tumbles. A slow thump that repeats once with each turn of the drum, which often points to a flat spot or a worn roller. A drum that turns more slowly than it used to, or a load that bunches in one corner and stays there. Cycles that run longer than before for the same load. A burnt rubber smell. Most of these are worth a closer look. The smell is the one that means stop running the dryer now.
Log the pattern before you touch anything
Keep a short note on paper or in your phone. Write down the load size, the cycle, the sound, and the point in the cycle where it starts. Note whether the sound comes on at the start, in the middle, or only when the drum is full. A pattern that repeats across several loads tells you more than one noisy run. Once you have it, you can describe the problem clearly to whoever looks at the machine, and that saves time.
Check it yourself, safely
Unplug the dryer before you open any panel. Open the access panel the way your owner's manual describes. Look at the belt for glossy or glazed surfaces, cracks, fraying, or a flat spot where it has slipped. Turn the drum by hand and feel for roughness or a point where it drags. Check the idler pulley for wobble and the spring for stretch. Look at the drum support rollers for flat spots, cracks, or a shaft that has worn loose.
If the belt is intact, the sound may come from the idler, a roller, or a small object caught near the drum. Clear whatever debris you can reach. Do not force the drum, and do not run the dryer with the panel off. If the dryer runs on gas, leave the burner area and the gas line to a qualified technician.
Decide who does the repair
Many households replace a belt themselves, provided the power is off and the steps above feel within reach. Stop and call a qualified technician if you smell burning, see scorching on the belt or inside the cabinet, find a broken spring, or cannot reach the part without disconnecting gas or electrical connections.
Before you agree to a repair, ask a few specific questions. Ask whether the belt, idler, and rollers are billed separately. Ask whether the visit includes a check of the vent path, since a restricted vent adds strain to the motor and the drum. Ask which part numbers they plan to use. Ask for the old parts back if you want to see the wear for yourself.
Put the repair next to the age
A belt is a small repair. The planning question is what the dryer has left, not only whether this part can be fixed. Find the install year, then compare it with the typical service life and when to plan for a clothes dryer. If the dryer sits early in its planning window, a belt and roller repair fits the plan well. If it sits late in the window, record the repair in your replacement notes and start comparing models. Either way, write the repair date beside the install year so the next decision starts from a complete record.