Maytag dishwasher won't clean inside glasses

[RayBeeman]

I have an older Maytag dishwasher that will not clean the underside of glasses, bowls, etc. I have replaced the thermostat as the heating element was not working. I cleaned the rotating arms of small debris. I also disassembled and cleaned every part to the bottom of the inside assemblies. The large filter was filledwith debris, so I pried it apart and cleaned it out as well. I don’t think the lower arm is spinning like it should. When I open it up in the wash cycle, the arm is barely moving. Do you have any solutions? Thank you.