Product review (5 stars): Make your dryer Happy  :-)
My Whirlpool Gas Dryer Model LGR5636JQ0 was heating intermittently, and taking longer and longer to dry.  These worked perfectly. Just watch a couple videos on Youtube and it is a Super easy job to replace these.  Plus while you have your machine open, I Suggest take a little extra time  to release the belt and lift out the drum so you can clean all the lint out of the machine (its a Fire Hazard).
Then clean the rollers and belt tensioner, try spinning the 3 rollers, then add a couple drops of oil to the hub of the drum rollers and spin them, you will see how big a difference it makes.  Then Reassemble and you have a quiet, efficient, and happy dryer  :-)