The dryer was making a sound almost like a dump truck backing up [Squeal!.....Squeal!.....Squeal!]. After some research, I decided that it must be the rear bearing. I also ordered a new belt since my Kenmore dryer is about 10 years old and replacing the belt is easy once you take the drum out. I've read that at about 10 years, the belts go south.
Getting the drum out wasn't hard, after removing the top and front panels (I left all the wires hooked up to the front panel) just unhook the belt from the motor and idler pulley and use it to lift upward. I had to jerk it up about 5 times before it would come out. Pay close attention to where the ball bearing is in relation to the plastic cup and the retainer that mounts to the back of the unit before you disassemble it.
Putting the bearing cup and retainer in place is easy when the dryer is pulled completely away from the wall so that you can get to the rear of the unit and the inside of the back wall at the same time.
The hardest part was attaching the new bearing stud ball piece (the part that looks like a little doorknob on a big flange). The screws are phillips head and are also self tapping. Getting these screws started without stripping the phillips drive was very challenging. It takes quite a bit of pressure to keep the drive engaged. I ended up placing the drum on the floor so that the bearing stud flange was pressed up against the rear drum wall. This way the bearing stud was pushing back as I pushed down to get the screws to bite. I also found that using a brand new bit that looked almost too big for the screw in a drill allowed me to push very hard while letting the drill to the turning. The screws then went right in.
All of the above took about 30-45 minutes. I spent another 45 minutes or so cleaning out lint. Then I greased up everything with the included grease and reassembled the dryer. When I was putting the belt back on, the idler assembly and spring came completely off, but I found it was intuitive to put back (no fasteners, just hook the arm on the pivot and rehook the spring). I did a test run before I put it back under the cabinet. I heard some noises which turned out to be coins caught in the tumbler fins. I removed the top and was able to remove the offending fin without taking the front off. Found 50 cents!
The dryer works good as new now. Very quiet and it dries faster now with all the lint gone.