I have an old Kenmore Elite gas dryer which was extremely noisy. Research brought me to the conclusion to replace the drum support rollers and the idler pulley assembly. Instead of just replacing the idler pulley I decided to purchase the assembly since it had a new shaft which I was concerned was worn too. I found a video for my exact model elsewhere. My model is much older than those included on this site. When replacing the drum support rollers I applied some Super Lube to the shafts. I did the same for the idler pulley shaft too. I bought four Tri-Rings just in case I needed them. I did not since the ones there were fine and did not break. I also bought just the idler pulley just in case I wanted to go that route and replace just it instead of the assembly. Upon inspection of my assembly I did not like how the pulley was spinning so I decided to replace the whole assembly.
In my order I also ordered a relay but that was for a different problem with the dryer. My dryer was turning off intermittently before the cycle was done. My specific symptom was that when the dryer quit if I held in the start button the drum would spin but once I released it it would stop. There are two relays used (same part) and one of them is for the motor. Replacing that one solved that problem.