Frigidaire model flsg72gcs9.
The dryer would not start so I took the front panel off and saw that the drum glide felts were damaged and coming loose. I replaced the top and bottom felts. I stretched the bottom felt too much when installing and snipped off about a 1/4” extra. After reinstalling, the dry went for about 15 minutes before a low rumbling could be heard which got louder as it went on.
I took the machine apart and noticed the pulley wheel had a crack so I ordered a new one along with a new belt. Replaced them and got the same result. (the belt leaves shaving or rubber dust underneath the pulley)
I ordered a new drum bearing even though the old one looked good and replaced it. Same result.
At this point the motor would not turn without assistance so I thought it was bad bearings and installed a new motor (and blower housing it comes with). Same rumbling, maybe even worse.
I noticed when I pushed on the back of the dryer the rumbling would stop and noticed on one of the corners it was missing a screw. I had to drill through the hole to get to where it secures the intake to the back round plate. Still continued to rumble.
The rumbling did not start until after I installed the new felts. They have had to be replaced a few times over the years. The left side of the felt has rubbing marks because the drum leans to one side creating a gap on one side and rubbing against the other. But I think it has always done this. I have leveled the dryer but the drum still leans that way.
Whenever I reinstall the drum it runs fine for 15 min to 45 min
The only thing I have not replaced is the blower fan but the dryer runs fine with the belt off and starts rumbling as soon as I put the belt back on.
Link to noisehttps://www.youtube.com/watch?v=UBEpPDqO