washer makes a loud grinding noise during the spin cycle, sounds like metal on metal.

Diagnosis

The loud, metal-on-metal grinding noise during the high-speed spin cycle on the Samsung WA50R5400AW is typically caused by the failure of the spider arm (the flanged pulley assembly). This component is made of an aluminum alloy that is susceptible to galvanic corrosion. Over time, detergent residue and minerals build up, eating away at the metal until one of the three arms develops a hairline fracture or snaps entirely. When the arm fails, the inner stainless steel tub loses its center of gravity. As the motor accelerates to spin speeds, the tub begins to wobble violently, causing the inner drum to rub directly against the outer plastic tub or the heating element/sensor housing. You can confirm this by reaching into the drum while it is off; if you can lift the inner tub upward or wiggle it independently of the outer tub, the spider arm is compromised. If the noise only occurs during the transition to high RPMs and sounds like a jet engine combined with a grinding gear, the bearing in the shaft has likely collapsed due to water leaking past the seal.

How to Fix It

Replacing the spider arm and tub assembly is a major overhaul that requires a complete teardown of the machine. Because the spider arm is often integrated into the tub assembly for this specific model, replacing the entire drum unit is the most reliable way to ensure the machine is balanced.

1. Disconnect the power cord and water supply lines. Remove the top console by unscrewing the rear panel screws and sliding the top cover backward.
2. Remove the agitator and the pulse protector (the center cap). Use a socket wrench to remove the large center nut holding the tub to the drive shaft.
3. Disconnect the wiring harnesses for the water level sensor and the drain pump.
4. Unbolt the suspension rods from the chassis. You will need to lift the entire tub assembly out of the cabinet.
5. Once the tub is removed, separate the inner stainless steel drum from the outer plastic tub by removing the perimeter bolts.
6. Remove the damaged spider arm (Part DC97-15232A or equivalent assembly). Clean all corrosive residue from the shaft using a wire brush and degreaser.
7. Install the new tub assembly, ensuring the drive shaft is seated perfectly flush. Apply a thin layer of waterproof silicone grease to the shaft seal to prevent future leaks.
8. Reassemble the suspension rods, reconnect the electronics, and run a "Calibration Mode" cycle to ensure the tub is centered.

If That Didn't Work

• Check for Foreign Objects: If the noise is more of a "scraping" than a "grinding," a bra wire or coin may have bypassed the drum holes and is rubbing against the rotating base. Use a flashlight to inspect the gap between the inner and outer tubs. You may need to remove the heating element or the pump filter to retrieve the object.
• Inspect the Drive Belt: A frayed or slipping belt can create a high-pitched screeching or grinding sound. Inspect the belt for black rubber dust around the pulley. If the belt is cracked, replace it and check the pulley alignment.
• Replace the Main Bearing: If the tub is stable but the noise persists, the main bearing has failed. This requires pressing the old bearing out of the outer tub using a hydraulic press or a heavy-duty puller and installing a new sealed bearing.
• Check the Suspension Springs: If the tub is hitting the side of the cabinet, the suspension rods may have lost their tension. Replace all four rods as a set to ensure the tub remains centered during the spin cycle.

Heads Up

• Avoid using excessive amounts of high-efficiency (HE) detergent; soap buildup accelerates the corrosion of the aluminum spider arm.
• Run a "Tub Clean" cycle with a commercial descaler once a month to remove the mineral deposits that lead to galvanic corrosion.
• Never overload the washer with heavy blankets or rugs, as this puts extreme centrifugal stress on the spider arms and can cause immediate failure.
• If you notice the washer "walking" across the floor during the spin cycle, stop immediately and check the leveling legs; an unlevel machine puts uneven pressure on the bearings.