Here are your parts
Replacement parts for General Electric GSD6600G00BB Dishwasher | AppliancePartsPros.comI am assuming that you have checked in the sump and it is free of debris.
Also that there is nothing wrapped around the chopper.
Also that the holes in the spray arms are clean.
Most units fill to just under the heating element.
You can check this by adding a couple quarts of hot water just after the fills during a cycle.
Often a symptom of a low fill is a growling noise during washing, the pump is sucking in air.
Just be sure to not overfill it.
If the mid and top arms now spin, it is probably a low fill problem.
If it is low fill the most likely culprit is the screen filter on the input side of the valve is partially clogged.
Remove the valve and clean the screen.
Do not permanently remove it from the valve as it is there to keep crud out of the valve which could hold the valve open and cause a flood.
Check that the water level is the same at the start of a wash cycle and just before it ends.
Could be that the flapper valve (Item328 in Section 5) is not sealing correctly and some of the water is being pumped out during the wash cycle.
Have you changed your dishwasher soap?
Powdered soap is still the best.
Liquid is good for non-heated cycles.
Tabs and pucks often cause problems.
Also different brands react differently if you have hard water.
Make sure that the rinse aid is full.
Here is a good link on dirty dishes
http://www.applianceaid.com/drain_wash.htmlNote: At the bottom it shows how to check for lime residue on the dishes.
