maytag not getting dishes clean anymore

I have a maytag dishwasher that seems to be running its complete cycle but when finished the dishes are not clean. Has worked fine for the last 3 years any idea where I should start looking for any problems. Thank you in advance.

Hi.

Disassemble the wash pump from inside in order to get to the chopper ( #6 on the diagram), clean the screen and see if that will make a difference.

Here are the breakdown diagrams and http://www.appliancepartspros.com/06-pump-motor-parts-for-maytag-mdb7759aws0.html

Post the results.

Simon.