Here is the parts breakdown
Replacement parts for General Electric GSD5360F00SS Dishwasher | AppliancePartsPros.com

It is not all the same a GE uses a number of different pump designs.
Yours is the older more common design.
The sump is checked by removing the cover (Item 506 in Section 1). Be care ful when doing this as there is often broken glass in the sump.
A turkey baster or sponge will help you get the water out of it. If you do remove the water be sure to add a couple quarts of water to the unit before restarting. These pumps do not like to run when dry and can burn up the seals.

A common problem with this design is the piston and nut (Item 564 in Section 1). If it does not seal properly some of the water is directed back into the tub instead of out the drain. It is under the screened cover at the back of the tub. It unscrews. Remove any water in the tub when doing this.

[COLOR="DarkRed"]so on this model I remove the sump screen to clean around the sump and don't remove the sump itself to clean under the sump?[/COLOR]
Sort of you remove the sump cover and then the insert and then clean/check in the sump for debris. Take note how the insert in the sump goes, put it back wrong and the chopper will eat it.
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Also, the test of removing the spray arm and running the machine doesn't work for this model?[/COLOR]
Sorry never heard of a test with the spray arms removed.