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Replacement parts for General Electric PDW7880G00SS Dishwasher | AppliancePartsPros.com

Check in the sump to be sure that it is empty.
Be careful there may be glass in there.
Also check that there is nothing wrapped around the chopper.

Did you add a couple quarts of water to the unit before starting it?
Pumps do not like to run dry, they can burn up seals.

If the sump is clear you will have to pull the pump so you can inspect it.

Sometimes you can get the pump out without having to pull the unit out from under the cabinetry. Depends how the clamps holding it in are positioned. It is worth a shot as some units are a pain to pull out depending how it was installed.
Unplug the unit or turn the breaker off.
Use a sponge and/or a turkey baster to get as much water out of the sump as possible.
Loosen the clamps and undo the support hanger and gently remove the pump.
When replacing a light coating of grease, margarine etc. on the sump and tub connector surfaces will help slip it in easier.