When started, the motor would run but the drum would not turn.

After removing the bottom front panel using a putty knife to pry the upper left and right edges of the panel, I noticed that the long thin drum belt had broken. I went online to PartSelect, and using the Whirlpool model number, found the parts diagrams. Since the dryer is 20 years old, I decided to order the maintenance kit part# PS373087 which includes new idler wheels, retainer clips, and a tension pulley as well as the belt . I found a number of webpages that offer guidance in replacing the belt. Along with the instructions that came with the maintenance kit, I was able to do the repairs and have the dryer up and running in 30 minutes. Remember to remove the door springs before taking off the upper front panel. You only need to loosen the bottom screws on this panel. Leaving them in place helps to align and hold the panel when re-installing it.