The short answer
On a UniMac dryer, a dryer makes noise in only a few ways: something loose in the drum, a worn roller or idler, a belt on its way out, or something in the blower. The sound and when it happens will tell you which, and two of the four are owner-checkable in minutes. A commercial machine runs many cycles a day against a metered supply, so utilities and load discipline outrank component failure until they are ruled out.
What you are actually seeing
- A rumble that rises with drum speed — Rollers or the idler.
- A squeal at the start of each cycle — A belt or a dry idler.
- A thump once per drum revolution — Something caught in the drum seam, or a flat-spotted roller.
- A buzz you can feel through the floor — Levelling, or a cabinet touching the machine beside it.
- NEAR MISS — a burning or hot-lint smell with the noise — Stop the machine and clear the duct before running it again.
Causes, most likely first on this dryer
- Coins, buttons, studs or a shoe tumbling with the load — Ranked first on UniMac: a machine loaded by different people every hour gets everything left in every pocket, and coins are the commonest thing it gets. On this one, remember that it runs many cycles a day against shared utilities, so clear the utilities before the machine.
- A rhythmic slap or a squeal at the start of each cycle — Second: a belt that is going makes a noise before it breaks, so this noise is a warning rather than a failure.
- Something has reached the blower wheel — a coin, a pen or a hair clip — Third: a blower noise rises and falls with the fan rather than with the drum, which is how it is told apart.
- The motor itself — Last, and that is the point of the order: it is a genuine repair, it is less common than everything above it, and it is diagnosed by elimination rather than by ear.
Check in this order, and why
- First — run the machine empty for a minute and listen — A noise that disappears with an empty drum was never the machine.
- Then — listen for a slap that repeats at drum speed, loudest when the drum is loaded — A belt noise loads up with the laundry, which is how it is separated from a roller.
- Third — listen for whether the noise tracks the drum rotation or is constant — Constant while running points at the blower; once per drum turn points at a roller or the seam.
- Only then — only after the load, the levelling and the drum-by-hand check are all clear — A motor noise is constant whenever the machine runs and does not change with the load, which is why it comes after everything above it.
What an owner can safely check
- Run the machine empty for a minute — Empty drum, no load, short timed cycle. If the noise goes, check pockets and the drum seam for what caused it.
About 10 min
- STOP here if the next thing to check is behind a fixed panel — Everything above can be done without tools on live parts. Past this point it is a technician job.
Before you open anything
Safety
Switch the machine off at its breaker before reaching into the drum or taking a panel off, and on a gas machine shut the gas off at its valve as well. Never run a dryer with a panel off to watch what is making the noise. A noise with a burning or hot-lint smell means stop: lint is fuel and the duct is the first thing to clear. If you smell gas, do not switch anything on or off, leave the building, and call the gas utility or emergency services from outside.
When it stops being an owner job
Call when the drum feels rough or heavy turned by hand, when the noise is a squeal or a rumble that gets worse week by week, or when it continues with an empty drum and a level cabinet. Rollers, idlers, belts and bearings all live behind a panel. Stop the machine and call immediately for any noise that comes with a burning smell, and clear the duct before running it again.
Nearest pages of this class
What this page does not cover
This page is written for the UniMac dryer as a class, not for one family or one model line. Where a family-specific page exists for your unit it is linked above and it is the more specific answer. Deliberately not here: part numbers, wiring colours, torque figures and any measured value, all of which differ by family.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
