My dishwasher has completely stopped cleaning the dishes... the "crud" that is redeposited on the dishes has reached an all time high... even if we rinse the dishes first. Is there a filter that can be emptied like in a clothes washer? We do not have the manual as it was the washer installed in the home when we moved in.

Does the unit pump all the water out?
The drain line could be partially restricted.
Usually in the bottom of the unit there is a screen assembly that could be restricted.
There is also a soft food disposer part to the drain pump aswsembly. Its job is to munch up and soft food particles to allow them to go down the drain.

Any of these items can cause your problem.