This is the easy way to fix a squeaky dryer rather than total disassembly every time. Initially it is extra work, but it saves repeated disassembly of the dryer and eliminates buying a new roller. I used a angle grinder with a thin cutoff wheel to make the hole. This does not alter the structural integrity. Cutoff wheel leaves very sharp edges and a file should be used to remove the sharp edge. Then sand till smooth. There is exposed 240V inside. Only oil with the power unplugged. Cover with a metal plate to
prevent shock and spinning metal which would cause personal injury.
Once done, it is easy to oil the dryer when it starts squeaking again. This is not a permanent fix for the dryer. The wheel bearing is likely no longer porous and will not hold oil ever again in the metal . It does keep you from loosing screws, snap rings, breaking plastic guides and breaking you back trying to get the drum aligned. It also usually happens when the dryer is full of clothes. No need to drag them out.
A video truly fit for youtube. I bought this dryer used and broken 20 years ago and it sounded like a freight train when I got it. Purchased for $30 as it was only a couple years old, it is still going strong. The D shaft opening of the plastic fan had rounded out a little and rubbed so hard that the plastic edge of the fan cage had ground away. Some epoxy and a hose clamp fixed the mounting. A number 12 copper wire around the outside of the fan held the fan blades in place. It is also a good time to go in with an air compressor and blow out the lint where the filter mounts.
WARNING: NEVER DEFEAT THE DOOR INTERLOCK. With the door open there will be no airflow across heating element. This will burn out the electric heating element.
The rumbling noise reduced greatly once I swung the dryer back to where the floor was level. Once the edges have been filed, folding duct tape over the edges would be a good idea to further eliminate possible cuts.