Product review (5 stars): watch the you-tube videos for how to replace it
I picked this up along with the front bearing to stop my dryer from squeaking.  My original one was still in good shape, but since I had the dryer open already and this part wears out as well, I figured I would replace it at the same time.
There are a lot of youtube videos for how to replace this part by unhooking the belts and taking out the drum completely.  However, there is also another one where the guy does it without pulling the drum.  I used that approach when I was looking at my parts before the order and it's a whole lot easier than re-stringing all the belts and removing the drum