Why won't my Whirlpool (model # LSN1000KQ0) washer agitate at the low speed?

My whirlpool washer (model #LSN1000KQ0) was making loud noises about 2 weeks ago. I pulled out the machine and noticed all this black dust on the floor. I decided to replace the motor coupling. I was back in business but noticed it is still not sounding right.
As I was checking the agitator dogs (they look fine) I noticed that the machine only does high agitation (it does a good job at it and it spins just fine but still no low agitation.). So when in the delicate cycle or Perm press cycle it just makes a clicking noise.
Also after 7 loads with the new motor coupling there is more black dust under the machine.
Why won't the washer do low agitation and where is this dust coming from?

heathblue
July 2010