First symptoms were squeaking drum. This is probably when new glide strips might have been all that we needed. But I put off fixing it... and I put it off some more. Noises got louder, squeaking became screeching, then it started to vibrate loudly.
The front drum bearing (really just a plastic arch that the drum rides on) had broken, and with the drum in a canted position, the rear bearing sleeve got messed up too.
I ordered the front drum support bearing, and also a rear drum bearing sleeve (not the whole kit). An appliance repair place on youtube said the sleeve was most likely all you'd need on the rear drum bearing assembly.
Getting the front bearing support in was not a problem. It's just snaps into place. Be sure to get glide strips with your new bearing, one of mine was missing (probably fallen into a load of clothes and lost long ago), and the other one was cracked. I had to order those on a separate order. I temporarily used the cracked glide strip, and made another one for the other side from a large nylon zip tie (just zipped it through the slots), and that took care of the front bearing.
I slid the drum forward a few inches without removing the belt (you really don't have to take the entire drum out) to get to the rear bearing. The old drum bearing sleeve looked fine, and didn't want to come off too easily from the shaft on the drum, so I put the dryer back together with the old sleeve still in. Mistake! Upon re-starting the dryer, the squeaking was gone from up front because of the new front bearing, but it soon started that horrible vibration again, because the rear sleeve was bad.
About 10 minutes later, I had the new sleeve installed, and dryer is as quiet as new. :)
I used only a Phillips screwdriver (#2 I believe) for this job. Nothing else was needed. Unplug dryer before opening it up!