Product review (5 stars): You may only need the idler pulley wheel...check it out first.
At the end of the day all my Whirlpool 27 front  load dryer needed to  stop the nerve wrecking horrible screeching was the idler wheel, which was included. The instructions did not incude a front load model. Youtube video didn't either.  After a little investigation I found that all I had to do was remove the back panel, very easily replace the idler pulley wheel and I was golden.  I could have spent a couple hours removing the drum and replacing those driver wheels, and belt, too.  But I knew what the source of my aggrivation was and got it done.  Laundry all caught up. Merry Christmas to you and me!