Here are your parts
Replacement parts for GE GSD3960L00SS | AppliancePartsPros.com

You have to do more troubleshooting.
Is it trying to drain when it should?
Does it drain any of the water out or is there no draining at all?
Have you removed the drain hose from where it attaches to the house plumbing to check for a plug? Often crud will build up where the hose attaches to the plumbing.
Remove the sump cover in the middle of the unit in the tub and check that it is clogged up with debris. Be careful often there is glass in this area. Also note how the interior piece goes on, put it on wrong and the chopper will eat it.

Remove the kick plate
On the left hand side of the pump assembly you will see a solenoid.
Does this solenoid pull down and then the pump run when it tries to drain?
This solenoid opens/closes a flapper valve which directs the water either up through the wash arms (solenoid not activated) or out the drain (activated).

If it is partially draining the piston nut assembly is s common cause of this.