Hi everyone, I’m new here and tried searching for an answer before posting so my apologies if this is a problem with an obvious solution … I’ve had my Bullet for a year and have done 75 or so roast cycles with no issues until today. The roaster is making a high pitched squeaking pulse sound when the drum is turning. I took off the front plate and cleaned and re-lubricated the ball bearing, but that didn’t make a difference. It definitely sounds different than the grinding sound that happens when the drum isn’t pulled all the way forward. And it’s not the set screw in the door handle because the roaster squeaks whether the door is open or not. The roaster still functions fine but I’m equal parts concerned and annoyed. I’d be grateful for any ideas or thoughts you may have, and thank you!
Most likely a bearing issue. You could try to lubricate both bearings with some food grade oil. Normally this solves the problem.
Hi Jacob, thanks for your reply. Is there an easy way to describe how to access the back bearing?
I did have a experience that the screw of the handle on the front door protrude and interfering with the drum.
I would also like to know how to lube the back bearing.
Not sure if there is an easy way. It involves loosening the pulley on the drum shaft, then taking off the front and pulling out the drum enough so that the pulley can be moved and you can see the bearing. Not a huge deal, but good to have someone to help when you put it back together. Be careful that that drum does not scratch the roast chamber around the drum, which is rather fragile.
While looking for something unrelated, I ran across this video from Aillio.
The video is about more than just “Pully Alignment” because it also touches upon Drum removal (which I had not seen done before). As Jacob said, it appears to be a bit more involved to remove the Drum because of all the stuff that has to be removed first. But, it could be done for those that want to give it a go. I do love that we can access, remove and replace parts on the Bullet. 
Thanks everyone! I really appreciate being a part of this knowledgeable and spirited community.
Thanks for all your help. I was having a chirping sound coming from the back of my machine. Turns out one of the screws fell out of the pulley, and was caught in the other chamber that @papascup had the link of how to get into.