Just curious but when was the last time you cleaned the drive motor or oiled the bearings? reason I ask is, shaded pole motors (which is what stove builders use), have very little torque output and dried out bearings can prevent them from rotating. That is why they drive through triple reduction gearboxes. The main reason why builders use them is they can have their rpm altered by increasing or decreasing the applied voltage and they are very inexpensive to produce.
Even an excessive buildup of dust and lint can stop them from rotating.
Most new drive motors utilize a ball bearing on the outboard side but on the drive side, the bearings are still oil impregnated bronze, which leads me to another point and that is, have you ever greased the reduction gearbox?
My stove (though not the same brand as yours), I have never replaced a drive motor or reduction gearbox. I clean and oil all my motors yearly (prior to spring shutdown) and I grease all my gearboxes as well. I've found (from taking them apart) that the builders of the gearboxes and motors use the minimal mount of lubricants. Keep in mind that no matter what brand of stove you have, neither the motors nor the gearboxes were made by the builder, they all buy them from second tier suppliers and incorporate them into their respective units. I've found taking them apart (not hard really) that most lack adequate internal lubrication and the atmosphere that they operate in causes that minimal amount of lubricant to get hardened and provide no lubrication what so ever, so the gear train is essentially running dry. That coupled with dry motor bearings or an excessive build up of dust and crud can adversely impact things like auger rotation of convection or draft fan speeds and dry bearings can and will contribute to distribution fan harmonics adversely. Nice thing about a shaded pole motor is, it can run with a totally locked rotor (armature) and it won't destroy it. The field laminations just get warm. That's it.
When I took apart my gearboxes and cleaned them of all the old, dried out grease and repacked them with high quality synthetic grease, I also drilled a and tapped a hole in each one to accept a grease fitting and every spring, they all get a couple pumps of grease until I see it coming out around the bronze bearing on the input side of the motor, like I said, over 20 years now and never replaced any drive components or a room air fan or a draft fan and our units runs 24/7 all winter except for cleaning.
