The answer, before the detail
Short answer: listen to the character of the sound. A thump is a roller or a flat spot, a squeal is a belt or a bearing, a rattle is something loose. On this dryer, cabinet touching a wall or the washer next to it is the likeliest of them.
What you observe
- A rhythmic thumping that matches the drum turning — Something on the drum's rotation: a worn roller, a flat spot on one, or a heavy item balled up inside.
- A scraping sound with the drum turning — Something rubbing where it should not: a worn drum glide or an item caught between drum and bulkhead.
- The noise stops when the machine is empty — A load-related noise, which means nothing inside the machine has failed.
- NEAR MISS — the drum will not turn at all — Noise with no rotation is a no-start fault. The belt and the motor are the suspects, and another page ranks them.
Causes, most likely first on a Klasse Unique dryer
- Cabinet touching a wall or the washer next to it — A dryer vibrates constantly. Standing level and clear, that vibration is quiet; rocking on one foot or touching the machine beside it, the same vibration becomes a drumming that fills the room. First, because nothing else on the list explains as many of these calls, and ruling it out costs nothing but a few minutes. A smaller brand rarely publishes a service manual to the public, so the order below leans on what is visible from outside rather than what a schematic would tell you.
- Something from a pocket rattling in the air path — The test is decisive: run the machine empty. A noise that disappears with an empty drum is the load, and a noise that continues is the machine. It takes second place because the check is quick and because leaving it unchecked makes everything below it harder to read.
- Drum support rollers worn or flat-spotted — At the front the drum runs on glides or a felt seal, and when those wear through the drum begins to scrape against the bulkhead instead of sliding on them. It sits here because it is a genuine cause with a narrower set of circumstances behind it.
- A belt that has stretched and now slaps — The drum is turned by a long thin belt held in tension by an idler pulley. The belt frays with age and slaps as it passes; the idler bearing dries out and squeals, usually louder cold and quieter once warm. Least likely of the four, and the one that only makes sense once the others are ruled out.
The order that finds it fastest
- Check nothing touches the machine at the back or the sides — Including the duct: a rigid duct hard against a wall transmits vibration as well as air. Start at this check: it is the one most likely to end the job on its own.
- Feel round the drum seam and the front lip with the power off — Coins and buttons lodge in the seam and in the gap at the front, where they are easy to miss. Second, once the first check is clean.
- Note whether the noise tracks the drum speed rather than the motor speed — A thump once per drum revolution is the roller signature. Third: by now the answer is usually already in hand.
What to do, step by step
- Adjust the feet until all four take weight and the machine does not rock — Check with a level across the top as well as by hand.
Tools: spirit level, adjustable spannerAbout 25 min
- Empty the drum, check the seam and the front gap, and run a short empty cycle — Do it with the power off while your hands are inside the drum.
Tools: torchAbout 15 min
- With the power off, turn the drum slowly by hand through several full turns — Listen and feel; the point where it catches tells you which part is worn.
About 15 min
- STOP when the next thing to move is a fixing rather than a cover — Anything held by fasteners is holding something in place for a reason. Write down what you found and leave it there.
Read this before you start
Safety
Unplug the dryer or switch off its breaker before any panel comes off — a large-appliance circuit is behind that panel and it is not a place to guess. Never run the machine without its lint filter in place, and leave the door switch wired as the factory ran it: a drum that can turn with the door open is a hazard.
When to hand it over
Stop and call when the noise comes with a burning smell or with the drum resisting by hand. Those two are the only urgent versions of this complaint; the rest can wait for a convenient appointment.
Other pages for this dryer
What is not on this page
Read this as the class-level answer. If a page exists for your particular Klasse Unique line, that page is more specific and more useful for your unit, and it carries the model detail this one cannot: fastener sizes, component positions and service sequences.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
