Product review (3 stars): You may only need the nylon sleeve part, which saves A LOT of time. Pre-thread the self-tapping screws!
I have a GE Profile dryer, circa 1997, on which I had previously replaced the front drum bushings. The squealing noise that occurred was not coming from the front, so I googled what else to look for. The 2 most likely culprits were the rear bearing and the idler pulley. Since you have to pull the drum for both, I figured why not replace both.  When I disassembled the unit (there are GREAT youtube videos on how to remove screws at the control panel and lower front structure to make the sides spread enough to facilitate removing the drum. Releasing the belt from the tension pulley is a critical step. Some tips: the bearing parts that go into both the drum back and the rear duct are not pre-threaded and use self-tapping screws. Thread these before installation. On my model, the drum back has two pieces that separate when you remove the bearing. The video recommends putting a nail in the hole to keep them aligned: I should have listened. Annoying to line them up properly. In my case, I could have bought just the nylon sleeve: the metal shaft and metal receiver looked fine to me. That would reduce the repair time substantially. Also, both the original and replacement bearing shafts had slots for retainer rings, but none was present on the old bearing or included in the new bearing kit.  I used automotive grease on the idler pulley and the bearing, but if I had to do it again I would have bought high temperature grease in advance. The reasons I gave this product a middling review is this: the nylon sleeve is really all that should be wearing out. The hardened steel pin looks indestructible. But the REAL kicker is that the instructions don't tell you how to get the nut on the back of the bearing shaft TIGHT. Mine loosened up and I had to disassemble the whole thing to figure out why the drum was banging around a few weeks later. You have to hold the nut with a socket and hit the flat sections of the housing with a hammer to tighten it (there is NO WAY to hold the shaft, which is smooth).