'86 Four Trax starter removal

Hi,

New to the forum. Recently read how to remove the starter on my 86 Four Trax, which I did. I removed the cover and gear next to the starter gear to allow for room to wiggle starter out. However, in the process, I removed the gear to the left with a shaft about 4 in long and 7/16 diam...which I should not have.

Now I am trying to put it back in place, but I have a washer about 1 in outer diameter that slipped out from shaft and I can"t figure where it fits! HELP!