Product review (5 stars): No More Squeaking/Shrieking Dryer
I had been living with the dryer making awful noises for a long time.  It was very squeaky, and it was getting worse.  I watched some videos online and started troubleshooting the issue. I figured it was probably either the rollers or the idler pulley. This kit had both, and was cheaper than buying the parts separately.  Once I got the dryer apart (piece of cake) I replaced the rollers.  The idler pulley in this kit was a different style than the one that was already there, but everything I've read says that they originally used the type with the wheel, switched to the C of metal, then swapped back to the wheel.  Well, I went ahead and put the new pulley in and it fit fine.  My belt looked like it was still in good shape, but I figured since I had a new one and was already inside the dryer, I'd put the new one on.  I closed the dryer and gave it a test run.  Ta-da, no more squeaking.  I'm not sure exactly which part fixed it, but I'm glad it is fixed.  I had to turn on the buzzer that sounds at the end of the load, since I can't hear it running anymore.

Everything was VERY easy to install.  It would probably help to have a second set of hands to help with the drum, but I did it alone without too much trouble.

Side note, the one I received did appear to be actual Whirlpool parts, not some cheap-o set.  I've seen a lot of complaints that non-whirlpool sets didn't quite fit right, so I tried to make sure I got the right brand of parts.  Interestingly, the Whirlpool parts kit was actually a few dollars cheaper than the other kit.  Make sure you comparison shop!