I was goofing with the pump last night. I believe the sound is not comming from the electric motor, but the impeller, like you said.

I am not sure how to get to the impeller.

this is the pump I have http://www.intheswim.com/Pool-Filter...-ground-pools/

I have tried to put my hand in the hole that sucks in the water but I can't reach in far enough.

Do I unscrew the motor?