My oven has 2 fans (upper/lower). These assemblies include new covers, and bushings & shaft-end nuts moved from old to new shafts without issue.
1 remove covers & fan blades inside the oven.
2 remove service cover from the rear of the oven after unplugging
3 remove 3 mounting screws per fan assy & unplug
4 reassembly is reverse of disassembly
The electrical plug on one of the new fans was wrong (wide vs. narrow spacing), but removing spade connectors from the plastic plug made the connection possible. both fans work fine & quiet.