Little Wonder self propelled leaf blower repair

I bought this model 9270-13-01 from Jacks about 8 years ago and it has worked flawlessly. Then the wheel drive suddenly stopped yesterday. I took off the bottom plate and I see that the rubber-edged drive wheel is hanging loose on the splined shaft that  it is supposed to be driving! There is a large hole in the middle where the shaft goes through it as if there was splined piece that used to be on the shaft but is now missing. Does anyone know how this driven wheel (P/N 4165111) is driven by the shaft?
Anyone ever repaired this drive and found that there was a missing piece? It seems to me that the bottom cover plate would have held in anything that fell out so I have no clue how this wheel connects to the splined shaft. If you know please tell me and provide a link to a picture that will help me understand. THANKS!