Here's the rest of the removal for the differential style.
A single roll pin keeps everything together.
With the roll pin removed the hub slides off.
The axle can then slide out and the spur gear removed. What was confusing was the hub on the other side seemed welded to the axle which was odd but that's the way Ariens did it. Most of the time they usually mounted the hub on the axle, keyed it and held it in place with a roll pin or cotter pin.
trouts2