My hangar door lift mechanism failed in very loud and noisy way. The key from the shaft+pulley keyway went missing allowing the shaft and pulley to slide instead of grip.
I took photos with my phone. But although my phone takes good photos when it is in focus it has always had trouble focusing. So most of the ones I have are blurry. These two are the only reasonable two.
The other pulley with a good key in the slot to show what it should look like. No split ring keeper on this one but the other one has one. The keys in the keyway look beautiful on this pulley.
The next photo shows the failure with the missing key, the slots not lined up anymore, the gap in the side of the pulley+shaft where the bore hole is now egg shaped and not ever going to fit snugly anymore, the split ring that next time I work with I will bring a pair of split ring pliers to remove instead of twiddling out with a pick and pliers. The keyway on the shaft is at the 3 o'clock position. The keyway on the pulley is at the 4 o'clock position in this photo.
Here is the HIGH RESOLUTION IMAGE of the failed assembly.
A trip to the farm store found a replacement pulley and a new key. Replacing the destroyed pulley with the new replacement was the fix. The door lift motor assembly now works smooth and quiet.