Rubber drive coupling disintegrated

Tried to follow the included instructions - no way that just prying the coupler off would work without bending the shaft and wrecking the threads! Then used a flat, open-ended 7mm wrench to hold the shaft and pliers to remove the coupling. The coupler was so tight that I could not unscrew it without the wrench slipping. Ended up shoving a screwdriver through the fanblade from the bottom (unplug it first!) and use the pliers to unscrew the coupler (remember, it's a left handed thread!)