This washer is a real workhorse. Have never had it serviced. I believe it is at least 20 years old. Everything is still working fine but the clothes have gradually been getting dry less and less. I inspected the belts. They appears dry rotted and there is little tension. Pump is working however I did notice some risidual water in the tub when I turned it on its back. Please give me you thoughts.
Very likely the problem is a bad pump belt. Nothing last forever. 
Replace both belts and adjust them as described in the attached instructions.
- The belts kit AP4011179
Here are the breakdown diagrams and http://www.appliancepartspros.com/partsearch/model.aspx?model_id=26567
Gene.