I had a call from a customer complaining of black smudges on her clothes, she thinks from her washer. She also reported that her dryer needed service because it made an awful noise.
Now, whenever I get a call about black smudges on clothes, I know it’s usually one of two things:
1) A chemical reaction between some detergents and fabric softeners can create black spots on clothes in the washing machine. You can tell if this is the case by seeing if the black spots will come off using soap and water. (Uncommon: if the spots will only come off using petroleum distillates, then this is oil from the washing machine’s transmission.)
2) Rubber and/or metal filings from a wallowed out drum roller in the dryer getting on the clothes. In this case, you’ll see amorphous smudges instead of well-defined, circular spots.
Turns out that, on this service call, the source of the staining was definitely the dryer. When I started up the dryer, it emitted a loud rumbling. I shut it off immediately and disassembled the dryer. After removing the drum, I saw the source of the black smudges right away. You can see it below (click it for a larger view):
As you can see, the drum roller is nuked. Amazingly, the roller shaft was still serviceable. If you looked at the larger view, you may have noticed all the metal shavings on top of the motor and piled in the back corner. With the drum roller so wallowed out, the rear drum seal was sloppy and would let metal filings into the drum while the dryer was running. These metal filings get on the clothes and leave black smudges. I replaced both drum rollers, the belt, and the idler pulley. Since this was a Whirlpool-built dryer, these parts all come in a convenient rebuild kit.