I had a motor go bad on my Whirlpool GC900QPPQ and also broke the plastic gear that drives the compactor up and down. I ordered a new motor and gear set from Appliance Parts Pro. During the installation you have to remove the compactor to replace the plastic sleeves on the screw pins. When I reinstalled the compactor I did not take notice of the directional switch arm and ultimately snapped it off.
I love Appliance Parts Pro and have bought from them to repair two other appliances in the house. It is even better that I get the parts the next day from their warehouse, even on Saturdays.