Hi Becky,
To remove the lower spray arm you have to unscrew the spray arm cap (#34 on the
pump & motor break down diagram) first.
I would recommend to replace it instead of cleaning because it's not expensive part.
Also I would recommend to remove the pump cover (#4 on the
pump & motor break down diagram) and check the pump housing filter (#6 on the
pump & motor break down diagram) and the rinse arm assembly (#7 on the
pump & motor break down diagram).
If they are clogged, it's better to replace them too.
- The part number for the lower spray arm is
AP178746
- The part number for the pump housing filter is
AP2644606
- The part number for the rinse arm assembly is
AP403589
Here are the break down diagrams for the Maytag dishwasher
Model MDB4040AWB
Good luck.
Gene.