Dishwasher problem

We are having problems with our dishwasher. See Model number above. We ordered a new pump and it is installed but it is not pumping out the water on the last pump out cycle. It seems to pump out water on the first pump out cycles.

If you cancel it more than one time it will pump out the water completely.

Husband can be reached at 814-382-7715.

Thank you.

Here are the parts
Replacement parts for GE GSD4620Z02BB | AppliancePartsPros.com

Often this is caused by the Piston & Nut Item 564 in the Body Parts section .

It is under the slotted cover at the back of the machine.
It unscrews may be a reverse thread but I am not sure about this.
Check to see if it is sealing correctly.