Run the GE dishwasher on a regular or normal cycle setting, without adding any dishes in the racks. Pull up a chair and sit by the dishwasher's door so that you can easily see the control panel.
Find the "Washing" and "Rinsing" indicator lights on the control panel. The GE dishwasher will generally drain during and/or after these cycles.
Listen for noises as the dishwasher transitions from the washing to the rinsing to the drying cycles. Respective cycle lights will also come on, blink or change in some dynamic way. If you hear "clicking" and "grinding" then these are normal sounds that the dishwasher will make when it moves from the water-circulation to water pump-out mode. If you don't hear these sounds periodically, then the drain pump may be broken or malfunctioning.
Call a dishwasher service technician if you hear a rattling noise.
Load the washer with laundry and start a regular wash cycle. Pull up a chair next to the front of the washer so that you can monitor the control panel and the various cycles.
Find the words "Wash," "Rinse" and "Spin" on the control panel, depending on your washer's model. Your GE washer may use a rotating knob or lighted indicators to display when the machine is on these cycles.
Listen for noises as the washer moves from the wash and rinse cycles, into the spin cycles. If you hear "gurgling," "slurping" or "sucking" noises before or during the spin cycle, then the drain pump is not broken. Other normal drain pump sounds include "swishing" and "swooshing" noises, especially after the wash cycle that creates suds and bubbles that are being pumped through the drain.
Clean out the drainage pump, if you have a Spacemaker model washer and hear knocking when the machine is trying to drain. There may be foreign objects in the drain pump, creating knocks. Look in the owner's manual that is specific to your model number to learn how to complete this procedure. This troubleshooting procedure is not available in other GE washer models.
Contact a technician for service, if the knocking noise continues.