Whirlpool washer WTW4850HW1 grinding noise from underneath during spin when slowing down

Hi, I’m Mike, your appliance troubleshooting expert. When the grinding happens in spin, does the basket actually ramp up to full speed, or does it stay still or start/stop while the noise occurs?

Does the noise seem to come from underneath the washer, and is there any burning‑rubber smell or black dust shavings under the unit after a cycle?

Does it agitate quietly during wash, and if you run a drain/spin with the basket empty does the grinding still happen on coast‑down?

In an empty Drain & Spin, do you still hear the grinding as the basket coasts to a stop, and is there a brief ratcheting/chattering right at the end of spin?

Thanks—that pattern (only on coast‑down with a full load, agitation normal, noise from underneath) on your WTW4850HW1 points to the belt/clutch side rather than a bad gearcase bearing.

Most likely causes, in order:

• Drive belt slipping/glazed: Heavier loads add inertia, so the belt can slip and “grind” or squeal as the basket coasts down. Often leaves black rubber dust under the washer and sometimes a faint burnt‑rubber smell.
• Drive pulley/splutch assembly wear: The plastic cam and the one‑way bearing in the pulley can roughen up or loosen. When the basket back‑drives the transmission during coast‑down, you’ll hear ratcheting/grinding from underneath. This is common on these VMW belt‑drive Whirlpool units.
• Basket drive hub wear (under the agitator): Worn splines let the basket slip under heavier loads. It usually also shows up as a brief chatter when spin starts and clothes coming out wetter than normal.
• Gearcase bearing: Less likely here because it typically rumbles throughout the entire spin, not only on slow‑down.

Safety note: If you decide to look underneath, unplug the washer first—sharp edges and moving parts are hazards.

If you’d like, I can walk you through a few quick, safe checks (no special tools) to narrow it to belt vs. splutch vs. hub—want those steps?

Great—here are safe, quick checks you can do on that model to narrow it down.

Safety setup

• Unplug the washer and turn water off.
• Empty the tub. Tilt the washer back 4–6 inches against a wall and chock it with a wood block so it can’t tip. Watch for sharp edges.

Underneath inspection

• Remove the plastic belt cover under the machine (typically 2–3 screws).
• Look for black rubber dust or smear marks around the large drive pulley and belt. A burnt‑rubber smell points to belt slip.

Belt checks

• Inspect the drive belt: shiny/glazed surface, cracks, or missing ribs = slipping belt.
• Press the belt at mid‑span; light, firm tension is normal. If it’s very loose, it will slip under heavy loads as the basket coasts down.
• Rotate the large drive pulley by hand several turns. If the belt skitters or squeals, or you see rubber dust forming, the belt is suspect.

Pulley/splutch checks

• Grab the large drive pulley (the plastic/metal wheel at the bottom of the gearcase) and check for wobble; it should spin true.
• Check the center pulley bolt: if it’s obviously loose, that can cause grinding/rubbing on coast‑down.
• With the belt off (slip it off a pulley), spin the large pulley by hand both directions:
  • You should feel smooth rotation one way and a light “ratchet” feel the other. A rough, gravelly feel or loud clicking indicates a worn splutch/one‑way bearing.
• Inspect the plastic splutch cam faces under the pulley for rounded/chewed edges or plastic shavings.

Basket hub (optional, from above)

• Pop the agitator cap, remove the 7/16" bolt, and lift the agitator out.
• Look at the basket drive hub (the plastic piece with teeth/splines). If the teeth are worn/rounded or you see white plastic shavings, the hub is wearing—often shows up with heavier loads and during start/stop of spin.

What your findings mean

• Mostly belt dust, shiny belt, no pulley wobble: likely a glazed/loose belt.
• Belt looks good, but pulley ratchets roughly or has play/loose bolt: worn or loose pulley/splutch assembly.
• Teeth worn under the agitator: basket drive hub wear.
• Low chance here, but if you ever hear a deep rumble through the entire spin (even empty): gearcase bearing—tech job.

If you tell me what you see (dust, belt condition, pulley feel, and hub teeth), I’ll pinpoint the culprit and outline the simplest fix.